Scholastic Achievement and Demographic Characteristics of Home School Students in 1998
Lawrence M. Rudner ERIC Clearinghouse on Assessment and Evaluation College of Library and Information Services University of Maryland, College Park
Abstract
This report presents the
results of the largest survey and testing program for students
in home schools to date. In Spring 1998, 20,760 K-12 home school
students in 11,930 families were administered either the Iowa
Tests of Basic Skills (ITBS) or the Tests of Achievement and
Proficiency (TAP), depending on their current grade. The parents
responded to a questionnaire requesting background and
demographic information. Major findings include: the achievement
test scores of this group of home school students are
exceptionally high--the median scores were typically in the 70th
to 80th percentile; 25% of home school students are enrolled one
or more grades above their age-level public and private school
peers; this group of home school parents has more formal
education than parents in the general population; the median
income for home school families is significantly higher than
that of all families with children in the United States; and
almost all home school students are in married couple families.
Because this was not a controlled experiment, the study does not
demonstrate that home schooling is superior to public or private
schools and the results must be interpreted with caution. The
report clearly suggests, however, that home school students do
quite well in that educational environment.
By current estimates, there are
between 700,000 and 1,200,000 students enrolled in home schools in the
United States. Further, by all accounts, the movement has been growing
steadily over the past few years (Lines, 1998). Yet, there is very
little scientific literature concerning the population of home school
students or even large samples of home school students.
This study describes the academic
achievement levels and some basic demographic characteristics of a
large sample of students and their families. While the academic levels
of home school students are described in terms of public and private
school norms, this study is not a comparison of home schools with
public or private schools. Such comparisons would be fraught with
problems. Home schooling is typically one-on-one. Public schools
typically have classes with 25 to 30 students and an extremely wide
range of abilities and backgrounds. Home school parents are, by
definition, heavily involved in their children's education; the same,
unfortunately, is not true of all public or private school parents.
Home schools can easily pace and adapt their curriculum; public and
private schools typically have a mandated scope and sequence. The list
of differences could continue.
This study seeks to answer a much more modest set of questions: Does
home schooling tend to work for those who chose to make such a
commitment? That is, are the achievement levels of home school
students comparable to those of public school students? Who is engaged
in home schooling? That is, how does the home school population differ
from the general United States population?
Methods Bob Jones
University Press Testing and Evaluation Service provides assessment
services to home school students and private schools on a
fee-for-service basis. In Spring 1998, 39,607 home school students
were contracted to take the Iowa Tests of Basic Skills (ITBS; grades
K-8) or the Tests of Achievement and Proficiency (TAP; grades 9-12).
Students were given an achievement test and their parents were asked
to complete a questionnaire entitled "Voluntary Home School
Demographic Survey." A total of 20,760 students in 11,930 families
provided useable questionnaires with corresponding achievement tests.
The achievement test and questionnaire results were combined to form
the dataset used in this analysis.
This section provides descriptions of the achievement measures,
the questionnaires, the Bob Jones University Press Testing and
Evaluation Service, and the procedures used to develop the dataset.
Iowa Tests of Basic Skills (ITBS)
Home schooled students in Grades K-8 took
the Iowa Tests of Basic Skills (ITBS) Form L, published by Riverside
Publishing Company, a subsidiary of Houghton Mifflin. Developed by
University of Iowa professors, the tests were designed and developed
to measure skills and standards important to growth across the
curriculum in the nation's public and private schools.
The ITBS reflects more than 50 years of
test development experience and research on measuring achievement and
critical thinking skills in Reading, Language Arts, Mathematics,
Social Studies, Science, and Information Sources. The scope and
sequence of the content measured by the ITBS were developed after
careful review of national and state curricula and standards, current
textbook series and instructional materials, and research (Riverside,
1993). All items were tried out
and tested for ethnic, cultural, and gender bias and fairness prior to
the development of the final form of the tests. Data on a nationally
representative sample of public and private schools were collected in
1992 and used to form the initial national norms. The norms were
updated in 1995 by Riverside. This study used these 1995 spring norms.
Tests of Achievement and Proficiency (TAP)
Home schooled students in Grades 9-12 took
the Tests of Achievement and Proficiency (TAP), Form L, also published
by Riverside Publishing Company. The TAP was designed and developed to
measure skills and standards important to growth across the high
school curriculum. Like the ITBS, the TAP scope and sequence were
developed after careful review of national and state curricula and
standards, and current textbook series and instructional materials.
Developed as an upward extension of the ITBS, the specifications,
format, and design of the TAP tests are similar to that of the ITBS.
TAP is fully articulated with the Iowa Tests of Basic Skills (ITBS)
Form L (Riverside, 1993).
Background Questionnaires
Background questionnaires were designed by the staff of
the Home School Legal Defense Association (HSLDA). Questions were
determined by reviewing the questions in previous surveys,
prioritizing them, and selecting only those that were most germane to
the objectives of the study. Where possible, questions and responses
were made to match those used by the U.S. Census, U.S. Department of
Labor and the National Assessment of Educational Progress to
facilitate comparisons of home school students with students
nationwide. HSLDA designed the
survey to be much shorter than previous survey instruments. They also
sought to pose all questions in an objective format, rather than a
constructed response format. In keeping with this approach, HSLDA
worked with National Computer Systems to design forms to be computer
scanable, thereby removing the need for manual data processing.
Bob Jones University Press Testing and Evaluation
Service The Bob
Jones University (BJU) Press Testing and Evaluation Service is the
largest and oldest of four organizations providing home school
families access to standardized achievement tests. The Testing Service
began offering the Iowa Tests of Basic Skills and Tests of Achievement
and Proficiency in 1984. In subsequent years they added other helpful
tools including practice materials, a personality inventory, and
diagnostic tests. In 1993, the Stanford Achievement Test series was
added as BJU Press assumed the testing that the Home School Legal
Defense Association had been providing for its members. Since that
time, a full range of writing evaluations (grades 3-12) and a career
assessment have been added to the growing number of evaluation tools
offered by the Testing Service.
Just as home school families were the impetus behind the start of the
Testing Service, home school families continue to be the largest
sector utilizing the service. However, there are also a number of
private schools that have chosen to use the services provided. Testing
is provided for students throughout the United States and Canada, as
well as many foreign countries.
The BJU Press Testing and Evaluation Service sends testing materials
to qualified testers who administer the tests and return them to the
Testing Service for scoring. The results are then returned to the
parent. Many parents test primarily for their own information to
verify that their home schooled students are progressing academically
at a normal pace. Other parents use the results to meet a state
testing requirement or to provide documentation when they choose to
return their students to a public or private school setting.
Data Generation Procedures
The following steps were followed to produce the data
set:
- Parents contracted with Bob Jones University to be administered
the Iowa Tests of Basic Skills or the Tests of Achievement
Proficiency (39,607 students in probably 22,000 families).
- Bob Jones certified test administrators, many of whom were the
students' parents.
- BJU sent questionnaires and answer forms to the test
administrators.
- Tests and questionnaires were returned to BJU. BJU bundled the
tests and sent them to Riverside Publishers for machine scoring. BJU
bundled the questionnaires and sent them to National Computer
Systems for scanning. Unlike in previous studies, the parents did
not know their scores ahead of time.
- Electronic copy of the 23,415 test results and 23,311
questionnaire results were sent to the author of this report. These
sets were merged to provide 20,900 cases with matching
identification numbers. In order to weight by state public school
enrollment, 140 cases with missing state data were dropped. A total
of 20,760 students formed the initial dataset used in the study.
After we formed the dataset with 20,760 students, we asked for the
remainder of the 39,607 achievement test scores. We were informed
that it would not be possible to disaggregate the remaining home
school students from students in private schools also contracting
testing services.
Characteristics of Home School Students and Families
This section provides a description of
home school students and their families based on the 20,790
respondents to our questionnaire. The distribution of students by
state, gender, age, race, parent marital status, family size, mother's
religion, parent education, family income, television viewing, money
spent on educational materials, and other demographic characteristics
are identified and, where possible, compared to national figures.
State
As shown in Table 2.1,
respondents came from each of the fifty states. Several states,
including Ohio, Georgia, and Virginia, have exceptionally high
representation given their size. This is probably due to the fact that
these states require testing of home school students. To reduce the
effects of these and other overrepresented states, the data were
weighted in all subsequent analyses by the number of public school
students in each state. While we would have preferred to weight by the
number of home schooled students in each state, such data are not
available for all 50 states (Lines, 1998).
Table 2.1 Participating Home School Students Classified by
State
| State |
Freq. |
Percent of sample |
| AK |
61 |
.3% |
| AL |
181 |
.9 |
| AR |
42 |
.2 |
| AZ |
201 |
1.0 |
| CA |
815 |
3.9 |
| CO |
810 |
3.9 |
| CT |
54 |
.3 |
| DC |
17 |
.1 |
| DE |
28 |
.1 |
| FL |
860 |
4.1 |
| GA |
1547 |
7.4 |
| GU |
10 |
.0 |
| HI |
112 |
.5 |
| IA |
234 |
1.1 |
| ID |
28 |
.1 |
| IL |
451 |
2.2 |
| IN |
533 |
2.6 |
| KS |
319 |
1.5 |
| KY |
163 |
.8 |
| LA |
551 |
2.7 |
| MA |
343 |
1.6 |
| MD |
196 |
.9 |
| ME |
109 |
.5 |
| MI |
523 |
2.5 |
| MN |
794 |
3.8 |
| MO |
361 |
1.7 |
| MS |
25 |
.1 | |
| State |
Freq. |
Percent of sample |
| MT |
112 |
.5 |
| NC |
972 |
4.7 |
| ND |
100 |
.5 |
| NE |
126 |
.6 |
| NH |
176 |
.8 |
| NJ |
324 |
1.6 |
| NM |
189 |
.9 |
| NV |
53 |
.3 |
| NY |
942 |
4.5 |
| OH |
2484 |
11.9 |
| OK |
382 |
1.8 |
| OR |
67 |
.3 |
| PA |
532 |
2.6 |
| PR |
8 |
.0 |
| RI |
32 |
.2 |
| SC |
579 |
2.8 |
| SD |
27 |
.1 |
| TN |
322 |
1.5 |
| TX |
1126 |
5.4 |
| UT |
35 |
.2 |
| VA |
1608 |
7.7 |
| VI |
2 |
.0 |
| VT |
59 |
.3 |
| WA |
787 |
3.8 |
| WI |
246 |
1.2 |
| WV |
92 |
.4 |
| WY |
40 |
.2
| |
Student Age and Gender
Table 2.2 shows the distribution
of the respondents by gender and age. About 50.4% or 10,471 of the
respondents were females; 49.6% (10,319) were males. These figures are
comparable to that of the population of 3 to 34 years old enrolled in
school (see U.S. Bureau of the Census, 1998, Table A-2). Some 51.4% of
school enrollees nationally are male. The percentages are comparable
at all age levels.
Table 2.2 Participating Home School Students Classified by
Gender and Age
| |
Age at time of testing (in years) |
| |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
| Females |
507 |
879 |
1148 |
1318 |
1301 |
1248 |
1049 |
936 |
774 |
516 |
264 |
119 |
| |
56.1% |
51.7% |
50.2% |
49.2% |
52.4% |
50.6% |
47.2% |
50.5% |
50.7% |
51.0% |
49.3% |
57.5% |
| Males |
397 |
820 |
1141 |
1360 |
1181 |
1216 |
1174 |
918 |
754 |
495 |
271 |
88 |
| |
43.9% |
48.3% |
49.8% |
50.8% |
47.6% |
49.4% |
52.8% |
49.5% |
49.3% |
49.0% |
50.7% |
42.5% |
| Total |
904 |
1699 |
2289 |
2678 |
2482 |
2464 |
2223 |
1854 |
1528 |
1011 |
535 |
207 |
Student Grade
Home school student grade
placement was identified by their parents, presumably based on the
grade level of the instructional materials. That grade was used by BJU
to determine the test levels and used in this report as a grouping
variable. Tables 2.3 shows the distribution of respondents and the
nation by grade. There is a large difference in the proportions of
high school (grades 9-12) home school students and the nation.
Compared to the national data, a relatively small percentage of home
school students are enrolled in high school. Possible reasons for this
lower participation for high school students may be the relative
newness of the home school movement, early graduation from high
school, and possibly a desire on the part of some home school parents
to enroll their children in a traditional high school. The
distributional differences for students in grades 1 through 8 are
minor.
Table 2.3 Home School Students Classified by Grade with
Percents and National School Percents
|
Grade |
| |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
| Home school |
7.4% (1504) |
10.6% (2153) |
14.1% (2876) |
12.9% (2625) |
12.6% (2564) |
11.9% (2420) |
10.3% (2087) |
8.8% (1801) |
5.7% (1164) |
3.8% (775) |
1.6% (317) |
0.3% (66) |
| Nation |
9.1% |
8.8% |
8.9% |
8.7% |
8.6% |
8.7% |
8.7% |
8.4% |
9.0% |
7.9% |
7.1% |
6.3% | National data: US Census, 1997b, Table 254.
Student Race
Table 2.4 shows the racial
distribution of home school students in 1998 and for the students
enrolled in elementary and secondary public and private schools
nationally in 1994. The distributions are quite different. The vast
majority of home schooled children are non-Hispanic White. The largest
minority groups for home school students (not shown in the table) are
American Indians and Asian students who comprise some 2.4% and 1.2% of
the home school students, respectively.
Table 2.4 Racial Distribution of Home School Students
And the Nation, in Percents |
|
|
White (not Hispanic) |
Black (not Hispanic) |
Hispanic |
Other |
|
Home school |
94.0% |
0.8% |
0.2% |
5.0% |
|
Nationwide |
67.2% |
16.0% |
13.0% |
3.8% |
| (National data: USDE,
1996; Indicator 27) |
Marital Status
The great majority of home
school students are in married couple families. In contrast, only 72%
of the families with at least one child enrolled in school nationwide
are in married couple families (Bruno and Curry, 1997, Table 19).
Table 2.5 Home School Students Classified by Parents'
Marital Status
| Marital Status |
Frequency |
Percent |
| Divorced |
80 |
0.7% |
| Single (never married) |
44 |
0.4 |
| Married |
11,335 |
97.2 |
| Separated |
131 |
1.1 |
| Widowed |
55 |
0.5 |
| Missing data |
16 |
0.1 |
| |
|
|
|
11,661 |
100.0% |
Children at Home
Table 2.6 shows the distribution
of children in home school families and families with children under
18 nationwide. On average, home school students are in larger
families. Nationwide, most families with school-age children (79.6%)
have only 1 or 2 children with a mean of about 1.9 children per
family. Most home school families (62.1%) have 3 or more children with
a mean of about 3.1 children per family.
Table 2.6 Home School Families Classified by Family Size
with National Comparison
|
Home School Families
|
Nationwide
|
|
Number of Children |
Percent |
Number of Children |
Percent |
|
1 |
8.3% |
1 |
40.8% |
|
2 |
29.6 |
2 |
38.8 |
|
3 |
28.6 |
3 |
14.3 |
|
4 |
18.6 |
4 or more |
6.1 |
|
5 |
8.4 |
|
|
|
6 |
3.9 |
|
|
|
7 or more |
2.6 |
|
|
| National Data: US Census,
1997a, Table 77 |
Mother's Religion
We asked the home school
families to identify the religious preference of each student's mother
by selecting from a list of 27 religions. As shown in Table 2.7, the
largest percentage of mothers identified themselves as Independent
Fundamental, Baptist, Independent Charismatic, Roman Catholic,
Assembly of God, or Presbyterian. The religious preference of the
father was the same as that of the mother 93.1% of the time.
Table 2.7 Home School Students Classified by Mother's
Religion
| |
Frequency |
Percent |
| Independent Fundamental |
5,119 |
25.1% |
| Baptist |
5,072 |
24.4 |
| Independent Charismatic |
1,681 |
8.2 |
| Roman Catholic |
1,106 |
5.4 |
| Assembly of God |
838 |
4.1 |
| Presbyterian |
772 |
3.8 |
| Reformed |
685 |
3.4 |
| Other Protestant |
500 |
2.5 |
| Pentecostal |
459 |
2.2 |
| Methodist |
420 |
2.1 |
| Lutheran |
353 |
1.7 |
| Other Christian |
2,213 |
10.9 |
| Other |
1,572 |
6.2 |
| |
|
|
| Total |
20,790 |
100.0% |
Parent Academic Attainment
As shown in Table 2.8, home
school parents have more formal education than the general population.
While slightly less than half of the general population attended or
graduated from college, almost 88% of home school students have
parents who continued their education after high school.
Table 2.8 Distribution of Home School Students and Students
Nationally Classified by Parent Academic Attainment
|
|
Percent |
|
|
Did not finish high
school |
High school graduate |
Some college, no degree |
Associate degree |
Bachelors degree |
Masters degree |
Doctorate |
|
| |
Home school fathers |
1.2% |
9.3% |
16.4% |
6.9% |
37.6% |
19.8% |
8.8% |
|
| Nation males |
18.1 |
32.0 |
19.5 |
6.4 |
15.6 |
5.4 |
3.1 |
|
| |
Home school mothers |
0.5 |
11.3 |
21.8 |
9.7 |
47.2 |
8.8 |
0.7 |
|
| Nation females |
17.2 |
34.2 |
20.2 |
7.7 |
14.8 |
4.5 |
1.3 |
|
|
National data: U.S. Census
(1996; Table 8) |
|
Family Income
National data on family income
are available for 1995. As shown in Table 2.9, home school families
span all income levels. On average, home school families have a higher
income level than do families with children nationwide and all
families nationwide. The median family income level for home school
families in 1997 is about $52,000. The median income for families with
children in 1995, nationwide, was about $36,000.
Table 2.9 Distribution of Family Income for Home School
Families, Families with Children Nationwide, and All Families
Nationwide by Income Levels, in Percents.
| |
Home school |
Families with children |
All families |
| Less than $10,000 |
0.8% |
12.6% |
10.5% |
| $10,000 to $14,999 |
1.5 |
8.0 |
8.5 |
| $15,000 to $19,999 |
2.2 |
6.1 |
6.8 |
| $20,000 to $24,999 |
3.9 |
7.6 |
8.4 |
| $25,000 to $29,999 |
4.9 |
7.5 |
7.8 |
| $30,000 to $34,999 |
8.5 |
7.5 |
7.6 |
| $35,000 to $39,999 |
8.1 |
7.1 |
7.0 |
| $40,000 to $49,999 |
16.0 |
11.3 |
11.0 |
| $50,000 to $74,999 |
32.5 |
18.4 |
18.1 |
| $75,000 and over |
21.6 |
13.8 |
14.3 |
| National data: Bruno and
Curry (1997, Table 19) |
Television Viewing
The National Assessment of
Educational Progress collects information on the television viewing
habits of fourth-graders. Home school fourth-graders and
fourth-graders nationally differ markedly in terms of television
viewing. Home school students rarely watch more than 3 hours of
television per day; nearly 40% of the students nationwide watch that
much television.
Table 2.10 Fourth-grade students Classified by Hours of
Television Viewing
| |
Percent of students |
|
6 or more hours per day |
4 to 5 hours per day |
2 to 3 hours per day |
1 hour or less per day |
| Home school |
0.1% |
1.6 |
33.1 |
65.3 |
| Nationwide |
19.0% |
19.5 |
36.4 |
25.1 |
| National data: NAEP Math
1997 |
Computer Use
The Condition of
Education provides a tabulation of the percent of students
nationwide who report using a computer by frequency of use for 4th,
8th, and 11th graders in 1996. At each grade level, the distribution
of computer use in 1998 by home school students is different from that
of the nation in 1996. At each of these three grade levels, much
larger percentages of home school students never use a computer. At
the fourth-grade level, a much larger percent of home school students
use a computer every day.
Table 2.11 Computer Use among Home School Students
and Students Nationwide in Grades 4, 8, and 11, in Percent
| |
Grade 4
|
Grade 8
|
Grade 11
|
|
|
Home school |
Nationwide |
Home school |
Nationwide |
Home school |
Nationwide |
| Never |
28.2% |
11.4% |
37.1% |
23.3% |
40.5 % |
16.0% |
| Less than once a week |
29.4 |
16.3 |
28.9 |
29.2 |
28.9 |
34.2 |
| Several times a week |
21.6 |
62.5 |
18.0 |
30.7 |
17.5 |
31.8 |
| Every day |
20.8 |
9.9 |
16.0 |
16.7 |
13.1 |
18.1 |
|
National Data: Snyder and Wirt, 1998, Indicator 3.
|
Money Spent on Educational Materials
The amount of money spent in
1997 on home school education for textbooks, lesson materials,
tutoring and enrichment services, and testing ranged from less than
$200 to more than $2000. As shown in Table 2.12, the median amount of
money spent was about $400.
Table 2.12 Home School Students Classified by Money Spent
On Home School Education in 1997
| Amount |
Frequency |
Percent |
| <$200 |
3,718 |
17.9% |
| 200-399 |
7,035 |
33.8 |
| 400-599 |
4,467 |
21.5 |
| 600-799 |
1,962 |
9.4 |
| 800-999 |
985 |
4.7 |
| 1,000-1,599 |
1,630 |
7.8 |
| 1,600-1,999 |
247 |
1.2 |
| >2,000 |
411 |
2.0 |
| Missing |
336 |
1.6 |
|
|
|
| Total |
20,790 |
100.0% |
Other Demographic Characteristics
Compared to the nation, a much larger percentage of home school
mothers are stay-at-home mothers not participating in the labor force.
Some 76.9% of home school mothers do not work for pay. About 86.3%
that do work do so part time. Nationwide, in 1996, only 30% of married
women with children under 18 did not participate in the labor force
(US Dept of Census, 1997a, Table 632).
A very large percentage of home school parents are certified to
teach. Some 19.7% of the home school mothers are certified teachers;
7.1% of fathers. Almost one out of every four home school students
(23.6%) has at least one parent who is a certified teacher.
Only 7.7% of the respondents were enrolled
in a full-service curriculum program, i.e., a program that serves
students and their parents as a "one-stop" primary source for
textbooks, materials, lesson plans, tests, counseling, evaluations,
record keeping, and the like for the year's core required subjects
such as language, social studies, mathematics, and science.
Academic Achievement The
complete batteries of The Iowa Tests of Basic Skills (ITBS) and the
Tests of Achievement and Proficiency (TAP) were used to assess student
achievement in basic skills. The ITBS was used for home school
students in Grades K-8; the TAP for students in grades 9-12. Almost
all students took Form L; a handful took parallel Form K.
Achievement test batteries like the ITBS
and TAP are a collection of tests in several subject areas that have
been standardized and normed. Norms for all tests within these test
batteries are based on the same group of students at each grade level.
Such norms allow students to be compared with other students and
groups to be compared with other groups.
The primary purpose of the ITBS and TAP is to assess the
academic achievement of students in public and private schools.
Consequently, much of the test development effort is devoted to
identifying the content to be covered by these batteries. Riverside
Publishers follow a four step process: 1) content specifications, 2)
editorial review, 3) pilot testing, and 4) national norms development
and updating. The first and
most critical step is developing content specifications and writing
test items. This step involves the experience, research, and expertise
of a large number of professionals representing a wide variety of
specialties in the education community. Specifications are developed
which outline the grade placement and emphasis of skills. These
specifications draw heavily on an analysis of textbooks, research
studies, nationally developed subject matter standards, and national
curriculum committees. Once the
items have been developed and pilot tested, the final forms of the
tests are developed and administered to large standardization samples
to gather normative data and to develop scales.
The spring standardization sample for the 10
levels of the ITBS consisted of approximately 137,000 students from
public schools, Catholic schools and private non-Catholic schools. The
public school sample was stratified to assure adequate representation
based on geographic region, district enrollment, socioeconomic status
of the district. The Catholic school sample was stratified on
geographic region and diocese enrollment. The non-Catholic private
school sample was stratified on region and school type. The spring
standardization sample for the four levels of the TAP consisted of
approximately 20,000 students stratified on the same variables.
National norms were developed based on the combined weighted
distributions of all three school types: public, Catholic and
non-Catholic private. Catholic/private school norms were developed
based on the combined weighted distributions of the latter two groups.
For simplicity, the combined public, Catholic and non-Catholic private
school norms are referenced in this report as national norms or
public/private school norms.
The data from the standardization sample are used to develop a variety
of reporting scales, such as percentiles and grade equivalent scores.
The analyses in this report rely primarily on the Developmental
Standard Score (DSS) scale developed by Riverside Publishers. The DSS
is a number that describes a student's location on an achievement
continuum that spans grades K through 12. Table 3.1 shows the median
DSS and median age that corresponds to each grade level in the
national standardization sample. The DSS scale shows that the average
annual growth in DSS units decreases each year.
Table 3.1 Median Developmental Scaled Scores and Median Age for
the ITBS/TAP Spring National Standardization Sample
|
|
|
|
Grade |
|
K |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
| DSS |
130 |
150 |
168 |
185 |
200 |
214 |
227 |
239 |
250 |
260 |
268 |
275 |
280 |
| Age |
6.1 |
7.2 |
8.2 |
9.3 |
10.2 |
11.2 |
12.2 |
13.2 |
14.2 |
15.2 |
16.2 |
17.2 |
18.1 |
| Source for age medians:
Drahozal (1998, personal
communication) |
This same DSS scale is used
for all tests and levels of the ITBS and TAP. The main advantages of
the DSS are that it mirrors reality well, spans all grade levels, and
provides a quasi equal interval scale which has a variety of
attractive statistical properties. Most importantly, DSS scores can be
compared to each other and can be meaningfully averaged.
The main disadvantage of DSS scores is
that they have no built-in meaning. Reference points are needed to
interpret DSS scores. "Grade level" is one possible reference point. A
DSS score of 170 in reading, for example, is about equal to the
typical reading score for second-grade students in public and private
schools in the spring of the year. A more refined reference is the
percentile score that corresponds to each DSS score. The 170 in
reading, for example, corresponds to the 54th percentile of
second graders. That is, this score is better than the score received
by 54 percent of the second graders using the 1995 spring norms.
The reader should note that
while all tests of the ITBS/TAP have the same median DSS score at each
grade level, the distributions within each subject area vary. A DSS
score of 310 for a tenth grader in reading, for example,
corresponds to the 87th percentile. A DSS score of 170 in
mathematics for a tenth grader would place the student at the
79th percentile. Percentiles
are always defined in terms of a grade level. This can be problematic
when analyzing data for home school students. In this study, 24.5% of
the home school students were one or more grades above the grade
usually associated with that student's age (see Table 3.2). A strong
case can be made that rather than using the percentile corresponding
to the enrolled grade, as we did in this study, one should use the
percentile associated with the student's nominal grade, i.e., the
grade usually associated with the student's age. The argument is that
a 10-year-old home school student enrolled in 5th grade should be
compared to his age peers in 4th grade. The counter argument is that
the percentiles already consider the fact that students are not always
in their nominal grade since the standardization sample had students
above and below grade level. We initially analyzed the data both ways.
Rather than expose our analysis to criticism, we chose to take the
more conservative route by employing the enrolled grade.
While very meaningful, percentiles do not
provide a complete picture of a student's or group's academic
performance. In this study, we used grade equivalent scores as an
additional reference point for interpreting DSS scores. A grade
equivalent score approximates a child's development in terms of grade
and month within grade. A DSS reading score of 170 can be viewed as
the typical DSS score earned by students in the ninth month of the
second grade or a GES score of 2.9. Just as the percentile associated
with a DSS scores varies by subtest, so do the properties of GES
scores vary across subjects.
Grade Equivalent Scores are particularly useful for estimating a
student's developmental status in terms of grade. But, these scores
must be interpreted carefully. An GES Score of 6.3 in reading for an 9
year old in the 3rd grade, for example, clearly indicates that the
third grader is doing well. This does not, however, mean that the
third grader belongs in the 6th grade. It only means that the third
grader can read as well as a sixth grader.
The usual interpretation of a Grade Equivalent Score of
6.3 for a third grader is that this third grade student can read third
grade material as well as a sixth grader can read third grade
material, not that he or she can read sixth grade material. The DSS of
the ITBS/TAP, however, is unique. The DSS scales were developed by
administering the same special scaling test to students in grades K-3,
another common scaling test to students in grades 3 to 9, and another
to students in grades 8-12. Thus, in the scaling study, the third
graders did take the same test as the sixth graders in each subject
area.
Grade Placement
Home school students are able to
progress through instructional material at the student's rate. Thus,
it is easy for home school students to be enrolled one or more grades
above their public and private school-age peers. To evaluate the
frequency of advanced placement, we compared students' enrolled and
nominal grades. The enrolled grade was identified by the parents and
used to determine the ITBS/TAP level. The nominal grade is the public
school grade in which the student would normally be enrolled in based
on the child's month and year of birth.
As shown in Table 3.2, almost one fourth of the home
school students (24.5%) are enrolled one or more grades above their
nominal grade. While comparable figures nationally do not exist, one
research director in a large school district estimated that less than
5% of their students are enrolled above grade level.
Table 3.2 Home School Students Classified by
Discrepancy Between Enrolled and Nominal
Grade |
Enrolled minus Nominal
Grade |
Frequency |
Percent |
|
-2 |
58 |
0.3% |
|
-1 |
1,019 |
5.1 |
|
0 |
13,931 |
69.8 |
|
+1 |
4,637 |
23.2 |
|
+2 |
199 |
1.0 |
|
+3 |
58 |
0.3 |
|
Percentages do not sum to 100% due to a small percentage of
students outside this
range. |
Overall Achievement
Table 3.3 shows the median
scaled score (DSS score) for home school students on the Composite
with Computation, Reading Total, Language, Mathematics Total with
Computation, Social Studies, and Science subtest scores by
grade. The corresponding percentiles shown in the table are the within
grade percentile scores for the nation that correspond to the given
scaled scores. For example, home school students in Grade 3 have a
median composite scaled score of 207 which corresponds to the 81st
percentile nationwide. The median home school student in third grade
out- performs 81% of the third graders nationwide. As an additional
comparison, we provide the national median for each grade in the last
column. By definition this is the 50th percentile of students
nationwide.
Table 3.3 Median Scaled Scores (corresponding national
percentile) by Subtest and Grade for Home School Students
| Grade |
N |
Composite |
Reading |
Language |
Math |
Soc. Stud. |
Science |
National Median |
| 1 |
1504 |
170 (91) |
174 (88) |
166 (82) |
164 (81) |
166 (80) |
164 (78) |
150 (50) |
| 2 |
2153 |
192 (90) |
196 (89) |
186 (80) |
188 (85) |
189 (81) |
195 (86) |
168 (50) |
| 3 |
2876 |
207 (81) |
210 (83) |
195 (62) |
204 (78) |
205 (76) |
214 (83) |
185 (50) |
| 4 |
2625 |
222 (76) |
228 (83) |
216 (67) |
220 (76) |
216 (68) |
232 (81) |
200 (50) |
| 5 |
2564 |
243 (79) |
244 (83) |
237 (69) |
238 (76) |
236 (71) |
260 (86) |
214 (50) |
| 6 |
2420 |
261 (81) |
258 (82) |
256 (73) |
254 (76) |
265 (81) |
273 (84) |
227 (50) |
| 7 |
2087 |
276 (82) |
277 (87) |
276 (77) |
272 (79) |
276 (79) |
282 (81) |
239 (50) |
| 8 |
1801 |
288 (81) |
288 (86) |
291 (79) |
282 (76) |
290 (79) |
289 (78) |
250 (50) |
| 9 |
1164 |
292 (77) |
294 (82) |
297 (77) |
281 (68) |
297 (76) |
292 (73) |
260 (50) |
| 10 |
775 |
310 (84) |
314 (89) |
318 (84) |
294 (72) |
318 (83) |
310 (79) |
268 (50) |
| 11 |
317 |
310 (78) |
312 (84) |
322 (83) |
296 (68) |
318 (79) |
314 (77) |
275 (50) |
| 12 |
66 |
326 (86) |
328 (92) |
332 (85) |
300 (66) |
334 (84) |
331 (82) |
280 (50) |
It is readily apparent from Table 3.3 that
the median scores for home school students are well above their
public/private school counterparts in every subject and in every
grade. The corresponding percentiles range from the 62nd to the 91st
percentile; most percentiles are between the 75th and the 85th
percentile. The lowest percentiles are in Mathematics Total with
Computation subtest (labeled Math in the tables); the
highest in Reading Total. While the grade-to-grade increase in
national medians is 13 DSS points in the lower grades, the annual
increase for home school students is about 16 points. These are
exceptional scores and exceptional grade-to-grade gains.
As shown in Table 3.4, the same
superiority of median scaled scores holds when comparing home school
students to students enrolled in Catholic/Private schools. The
Catholic/Private school percentiles corresponding to median scaled
scores range from the 53rd percentile to the 89th percentile; most are
between the 65th to 75th percentile. In every area and every grade,
the median scores for home school students exceed the median scores of
students enrolled in Catholic/Private schools.
Table 3.4 Median Scaled Scores of Home School
Students (Corresponding Catholic/Private School Percentile) by
Subtest and Grade
| Grade |
Composite |
Reading |
Language |
Math |
Soc. Stud. |
Science |
| 1 |
170 (89) |
174 (86) |
166 (80) |
164 (80) |
166 (73) |
164 (75) |
| 2 |
192 (88) |
196 (84) |
186 (74) |
188 (81) |
189 (81) |
195 (85) |
| 3 |
207 (74) |
210 (74) |
195 (55) |
204 (71) |
205 (69) |
214 (80) |
| 4 |
222 (72) |
228 (72) |
216 (58) |
220 (69) |
216 (56) |
232 (76) |
| 5 |
243 (71) |
244 (72) |
237 (60) |
238 (68) |
236 (60) |
260 (82) |
| 6 |
261 (71) |
258 (71) |
256 (58) |
254 (65) |
265 (72) |
273 (77) |
| 7 |
276 (72) |
277 (77) |
276 (63) |
272 (70) |
276 (68) |
282 (73) |
| 8 |
288 (72) |
288 (75) |
291 (65) |
282 (68) |
290 (68) |
289 (67) |
| 9 |
292 (63) |
294 (70) |
297 (61) |
281 (56) |
297 (63) |
292 (59) |
| 10 |
310 (71) |
314 (81) |
318 (71) |
294 (57) |
318 (72) |
310 (66) |
| 11 |
310 (63) |
312 (72) |
322 (69) |
296 (56) |
318 (67) |
314 (63) |
| 12 |
326 (74) |
328 (81) |
332 (71) |
300 (53) |
334 (74) |
331 (72) |
The relationship between median composite
scaled scores for home school students, Catholic/Private school
students, and the nation is shown in the Figure 1. At each grade
level, the test performance of Catholic/Private school students is
above the national performance levels, especially in the higher grade
levels. Also at each grade level, the performance of home school
students is above the performance levels of students enrolled in
Catholic/Private schools. The differences between these groups are
considerable. For example, the median score for 7th graders nationwide
is 239; for Catholic/Private school students the median is 257; for
home school students the median is 276. Another way to look at this
chart is to examine the grades corresponding to a given composite
score. A composite scale score of 250, for example, is typical of a
home school student in Grade 6, a Catholic/Private school student in
Grade 7 and students nationwide in the later stages of grade 8.
Figure 1. Academic Achievement of Home School,
Catholic/Private and the Nation's Students
The Grade Equivalent Scores (GES)
corresponding to the median DSS scaled scores for home school students
are shown in Table 3.5. These GES scores indicate the performance
levels of home school students in terms of student grade placement
nationwide. The median composite scaled score for fourth-grade home
school students, for example, is 217. This is comparable to the median
score expected of students nationwide in the ninth month of fifth
grade. Compared to students nationwide, the median fourth-grade home
school student test performance is 1.1 grade equivalents above his
public/private school peers. By 8th grade, the median performance of
home school students on the ITBS/TAP is almost four grade equivalents
above that of students nationwide. Similar trends hold for all subject
areas. The reader should
recognize that the grade equivalent scale tends to magnify differences
at the high school level and that the percentile scale is more
meaningful in these higher grades. While 50% of eighth grade home
school students have scores that are 4 grade equivalents above the
public school median, so do some 20% of eighth grade students in
public schools. The revealing statistics are the percentiles which are
consistently high across grade levels and subject areas.
Table 3.5 Median Scaled Scores (corresponding Grade Equivalent
Scores) by Subtest and Nominal Grade for Home School Students
| Grade |
Composite |
Reading |
Language |
Math |
Soc. Stud. |
Science |
National Median |
| 1 |
170 ( 2.9) |
174 ( 3.1) |
166 ( 2.6) |
164 ( 2.6) |
166 ( 2.7) |
164 ( 2.6) |
150 ( 1.8) |
| 2 |
192 ( 4.1) |
196 ( 4.5) |
186 ( 3.8) |
188 ( 4.0) |
189 ( 4.0) |
195 ( 4.5) |
168 ( 2.8) |
| 3 |
207 ( 5.1) |
210 ( 5.5) |
195 ( 4.4) |
204 ( 5.2) |
205 ( 5.1) |
214 ( 5.8) |
185 ( 3.8) |
| 4 |
222 ( 6.2) |
228 ( 6.9) |
216 ( 5.9) |
220 ( 6.4) |
216 ( 5.9) |
232 ( 7.3) |
200 ( 4.8) |
| 5 |
243 ( 8.3) |
244 ( 8.3) |
237 ( 7.6) |
238 ( 7.7) |
236 ( 7.6) |
260 ( 9.8) |
214 ( 5.8) |
| 6 |
261 (10.1) |
258 ( 9.6) |
256 ( 9.4) |
254 ( 9.1) |
265 (10.4) |
273 (11.6) |
227 ( 6.8) |
| 7 |
276 (11.9) |
277 (12.0) |
276 (11.9) |
272 (11.3) |
276 (11.9) |
282 (12.5) |
239 ( 7.8) |
| 8 |
288 (12.9) |
288 (12.9) |
291 ( - ) |
282 (12.5) |
290 ( - ) |
289 ( - ) |
250 ( 8.8) |
| 9 |
292 ( - ) |
294 ( - ) |
297 ( - ) |
281 (12.4) |
297 ( - ) |
292 ( - ) |
260 ( 9.8) |
| 10 |
310 ( - ) |
314 ( - ) |
318 ( - ) |
294 ( - ) |
318 ( - ) |
310 ( - ) |
268 (10.8) |
| 11 |
310 ( - ) |
312 ( - ) |
322 ( - ) |
296 ( - ) |
318 ( - ) |
314 ( - ) |
275 (11.8) |
| 12 |
326 ( - ) |
328 ( - ) |
332 ( - ) |
300 ( - ) |
334 ( - ) |
331 ( - ) |
280 (12.8) | (The - sign indicates the scaled scores
are beyond the effective range for GES conversion.)
The grade
equivalent score comparisons for home school students and the nation
are shown in Figure 2. In grades one through four, the median ITBS/TAP
composite scaled scores for home school students are a full grade
above that of their public/private school peers. The gap starts to
widen in grade five. By the time home school students reach grade 8,
their median scores are almost 4 grade equivalents above their
public/private school peers.
Figure 2. Home School Students Compared to the National Norm Group
in Grade Equivalent Units
Years of Home Schooling
Almost half of the respondents
(47%) indicated that they have been home schooled for each grade prior
to their current grade, i.e., their entire academic life. Table 3.6
shows that students who are home schooled for their entire academic
life do better than students who have been home schooled for only a
few years (F academic life =108.2; df=1,9750; p<.01). There
is also a significant interaction between grade and years home
schooled (F=7.4; df=9,9750, p< .01), indicating that the
effectiveness of home schooling varies with the student's grade. The
differences are most meaningful starting in Grade 6.
[All F ratios reported here are
from a two-way analysis of variance with composite scaled scores as
the dependent measure, grade as a blocking variable, and one
independent variable. Because the students are within families, the
dataset was trimmed by randomly selecting one child from each family.
Had the full dataset been used, the variance of the children within a
family would have been artificially smaller than the variance of among
children in the population of inference. This would have increased the
risk of Type I error, showing significance when significance may not
be so. To assure adequate cell sizes, the analyses were also
restricted to Grades 1 through 10. A statistically significant
difference only means that there is evidence of a difference in
population values. The difference may be small and not meaningful.
"n.s." is used to indicate not significant.]
One reviewer questioned whether this significant
difference was due to life-long home schooling or was life-long home
schooling serving as a proxy for parent education or income. The
correlation of life-long home schooling and whether either parent has
a college degree is .12, indicating there is some, but not a great
deal of overlap between these variables. The correlation with income
level was .02, indicating no relationship. Thus, whether a student is
home schooled his or her entire life appears to be significantly
related to achievement.
Table 3.6 Composite Scale Score Mean, Standard Deviation and
Corresponding Percentile by Number of Grades Home Schooled and
Grade
| Grade |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
Home schooled entire academic life |
| Mean |
170 |
195 |
208 |
224 |
244 |
265 |
278 |
291 |
300 |
314 |
| sd |
12 |
16 |
17 |
20 |
23 |
23 |
25 |
26 |
27 |
23 |
| N |
479 |
743 |
863 |
608 |
552 |
444 |
319 |
242 |
159 |
100 |
| %ile |
92 |
95 |
85 |
81 |
82 |
85 |
83 |
84 |
83 |
86 |
|
Home schooled some grades |
| Mean |
168 |
192 |
206 |
222 |
241 |
256 |
270 |
282 |
288 |
299 |
| sd |
11 |
15 |
18 |
20 |
24 |
26 |
27 |
30 |
30 |
32 |
| N |
221 |
428 |
616 |
666 |
681 |
688 |
628 |
608 |
436 |
287 |
| %ile |
90 |
92 |
82 |
79 |
79 |
78 |
77 |
78 |
73 |
75 |
| Difference |
2 |
3 |
2 |
2 |
3 |
9 |
8 |
9 |
12 |
15 |
[The percentiles (%ile) shown in this and the
following tables are the within-grade percentiles corresponding to the
mean composite scale scores, differences and ranges refer to
differences in and ranges of mean composite scale scores, sd refers to
standard deviation, N is the number of students within each
cell.]
Enrolled in a Full-Service Curriculum
There is no significant
difference in the mean composite scaled scores of home school students
enrolled in a full-service curriculum and home school students not so
enrolled. As shown in Table 3.7, the means are quite close at all
grade levels (F enrollment=.24; df=1,9750; n.s.).
Table 3.7 Composite Scale Score Mean, Standard Deviation and
Corresponding Percentile by Full-service Curriculum Status and
Grade
| Grade |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
Not enrolled in a full-service
curriculum |
| Mean |
170 |
194 |
207 |
223 |
243 |
260 |
272 |
284 |
291 |
302 |
| sd |
12 |
15 |
17 |
20 |
23 |
25 |
26 |
29 |
30 |
31 |
| N |
646 |
1109 |
1361 |
1214 |
1145 |
1042 |
847 |
771 |
495 |
320 |
| %ile |
92 |
94 |
83 |
80 |
81 |
81 |
79 |
79 |
76 |
78 |
|
Enrolled in a full-service curriculum |
| Mean |
167 |
199 |
209 |
220 |
241 |
256 |
272 |
286 |
289 |
306 |
| sd |
13 |
17 |
18 |
21 |
24 |
29 |
31 |
30 |
30 |
28 |
| N |
54 |
63 |
118 |
60 |
89 |
89 |
101 |
79 |
100 |
67 |
| %ile |
89 |
97 |
86 |
76 |
79 |
78 |
79 |
80 |
74 |
81 |
| Difference |
3 |
-5 |
-2 |
3 |
2 |
4 |
0 |
-2 |
-2 |
-4 |
Student Gender
There are no significant
differences in the achievement levels of male versus female home
school students (F for gender=.01; df=1,9750; n.s.). As shown
in Table 3.8, the means are virtually identical at all grade levels.
Table 3.8 Composite Scale Score Mean, Standard Deviation
and Corresponding Percentile by Grade and Gender
| Grade |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
Males |
| Mean |
170 |
195 |
208 |
223 |
243 |
260 |
271 |
285 |
288 |
303 |
| sd |
12 |
15 |
18 |
19 |
23 |
25 |
26 |
30 |
33 |
33 |
| N |
355 |
576 |
749 |
639 |
600 |
597 |
479 |
428 |
294 |
181 |
| %ile |
92 |
95 |
85 |
80 |
81 |
81 |
78 |
80 |
73 |
78 |
|
Females |
| Mean |
169 |
193 |
207 |
223 |
242 |
260 |
274 |
284 |
293 |
303 |
| sd |
12 |
16 |
17 |
21 |
24 |
25 |
26 |
28 |
26 |
28 |
| N |
345 |
595 |
730 |
634 |
634 |
535 |
469 |
422 |
302 |
206 |
| %ile |
91 |
93 |
83 |
80 |
80 |
81 |
80 |
79 |
77 |
78 |
| Difference |
1 |
2 |
1 |
0 |
1 |
0 |
-3 |
1 |
-5 |
0 |
Money Spent on Educational Materials
There is a significant
difference in the achievement levels of home school students depending
on the amount of money |