Within the context of the SLS, a participant’s cohort is defined as those individuals whose birth year falls within a specific 7-year span. Over time, the lower cohort values tend to drop from succeeding datasets as the oldest cohorts leave the SLS. For example, the most recent SLS data wave (2005) no longer had participants born prior to 1900 and thus, the 2005 dataset does not include cohort values of 1 and 2. Cohort value remains consistent across time for participants.​

Data Wave:

To date, there have been eight occasions of data collection, or data waves, in the Seattle Longitudinal Study occurring in 7-year intervals: 1956, 1963, 1970, 1977, 1984, 1991, 1998, and 2005. These defining years of data waves typically spanned more than a calendar year for the data collection effort. For example, data collection for SLS 1970 could have started in late 1969 and continued until early 1971. The datasets currently on this website represent data from the first five waves of the SLS.

Independent Sample:

A file containing data for subjects who have participated for the first time in the SLS (first-occasion participants). Thus, a dataset named “ind1963” is the independent sample for the 1963 data wave and includes 1963 measurement data for first-ti​me participants only. Variable names in this dataset end with “63.”


SRA (Science Research Associates) Primary Mental Abilities, Ages 11- 17—Form AM (Copyright 1948, by L.L. Thurstone and Thelma Gwinn Thurstone). The PMA contains five, timed subtests and is administered in a group testing session. These subtests are:

  • Verbal Meaning. A 4-minute, 50-item test, which measures a participant’s ability to select the correct definition of a word from five choices.
  • Space. A 6-minute, 120-item test measuring the ability to rotated abstract figures in two-dimensional space. There are 20 groups of 6 items, from each of which the participant must select the two or three items, which can be rotated to match the stimulus figure.
  • Reasoning. A 6-minute, 30-item test measuring a participant’s ability to determine the pattern in a letter series and select the next correct letter from five options.
  • Number. A 6-minute, 70-item test that measures a participant’s mathematical ability to check addition problems and select whether or not the provided sum is correct.
  • Word-Fluency. A 5-minute test in which participants are asked to write down as many words as they can that begin with the letter S. Once a word is used, it cannot be used again in its past tense, as a plural, or in a series. Proper nouns are not allowed.

Once you have become an authorized user of the SLS website datasets, you will be able to view a pdf file of the PMA in its current format.


A dataset file containing repeated measures. For example, a repfile named “rep24” would contain data from the second through fourth wave of the SLS—the 1963, 1970, and 1977 times of measurement. Variable names in this dataset would end with “63,” “70,” and “77.”


Seattle Longitudinal Study


Test of Behavioral Rigidity (Form TBR-4, Copyright 1995, by K. Warner Schaie). In the first five data waves of the SLS (1956-1984), the TBR was administered as a single test booklet during a group testing session. It contained the Capitals Test, the Opposites Test, and the Questionnaire. In 1991, the Questionnaire section of the TBR was separately printed in a larger, more readable font and given to participants to complete as “homework.” The Capitals and Opposites Tests continued to be administered in the group testing session. Once you have become an authorized user of the SLS website datasets, you will be able to view a pdf file of the TBR in its current format.​