LSAL Project Design Highlights
The design of the longitudinal study is characterized by a number
of critical features:
Representative sample
A statistically representative sample adults ages 18-44 who, at the time
of screening, had not finished or were not currently enrolled in high
school, or gotten a GED and were proficient speakers of English (not necessarily
native speakers) allows generalization to the target population of interest.
Student and Non-student comparisons
In order to better understand the contribution of adult literacy programs
to the learning and literacy development of adults, LSAL compares the
experiences of two groups within the target population: adults who participate
and do not participate in the formal programs. People entering an ABE
program in 1998 at one of several area community colleges were recruited
into the study selection pool as a way to over-sample students for adequate
statistical comparison.
Learner-Centered
This is a learner-centered panel study rather than a program evaluation
design. Programs are not directly involved in collecting data about their
students for the LSAL or trying to follow them over time. Previous studies
using strategies dependent on programs have had methodological problems
because programs are not set up to follow individuals over time. This
is an important feature of the study because it shifts the focus on inquiry
from a program frame of reference to the experience of learners who move
in and out of programs.
Panel Study
LSAL is a panel study that has six data collection points over nine
years. The panel of 940 people who were interviewed in wave one are retained
in the study and were interviewed once a year between 1998 and 2001 (waves
1 through 3) and once every two years for waves 4 through 6. This design gives
6 points of measurement for modeling change over time and a spread of
nine years over which development and the outcomes of development can
occur.
Extensive Survey
An extensive background survey instrument organizes learning in multiple
contexts: formal education programs include ABE, work contexts, home and
family, and personal interests. Additional one time modules have been
added on including learning disabilities, turbulence in daily life, health,
and computer literacy.
Multiple outcome measures
Multiple outcomes will be tracked over time, including basic skills, changing
patterns of literacy and learning practices, and changes in a range of
social and economic activities. Both "hard" and "soft"
indicators are being collected wherever possible. For example, employment
and earnings data are being collected both through interviews and with
participants' permission from state administrative records; growth in
basic skills is being assessed through paper and pencil tests as well
as through interview questions and self report
Study comparisons
Many questionnaire items are identical or highly similar to ones used
in other major research projects in order to promote comparability and
utility of the data sets and research findings.
Multivariate longitudinal modeling
The research questions will be addressed with multivariate and multilevel
models. Because the LSAL is longitudinal the primary research questions
cannot be answered until all the data are collected and analyzed.
Sample Retention
A high quality sample has been recruited and retained despite the expectation
that it is difficult if not impossible to do so with this population which
is notoriously mobile and hard to locate. Through Wave 5, about 90% of the panel
is still in the study (even though some respondents are not interviewed in a given wave,
they return to participate in later waves). This outstanding figure is due to the attention,
planning and resources invested in the tracking and detective operations.
High retention improves the statistical power and validity of the final models and
findings.
| Wave Number | Retention Rate |
|---|---|
| Wave 2 | 90% |
| Wave 3 | 90% |
| Wave 4 | 86% |
| Wave 5 | 82% |
Qualitative Component
The project has a qualitative component that is working with a smaller
number of study participants in a more informal and intensive manner.
These qualitative case studies are being carried out with pilot subjects
from the survey, individuals who are not part of the formal survey sample
but who nevertheless receive the same interviews and assessments as individuals
in the formal sample. Because both the survey data and the richer qualitative
data are being collected independently from these individuals, the two
types of information will complement each other and help the project better
understand the strengths and limitations of the survey data.