The SLS Measurement Battery
The test battery includes the psychometric ability and rigidity-flexibility measures that have been collected since the inception of the SLS as well as additional markers for the ability factors included in the basic battery. The additional measures included mark the abilities of Perceptual Speed and Verbal Memory, as well as multiple choice items sampling real-life tasks. used as an ecological validity measure. In addition, for some test occasions, measures of certain personality traits, family environment, life-styles (including health behaviors), neuropsychological measures, and health history variables were added.
The Cognitive Ability Battery
The psychometric ability battery was expanded in 1984 to permit structural analyses that require multiple measures to mark each ability factor. In addition it introduces alternate forms that may have differential validity by age (see Schaie, 1978; Gonda, Quayhagen, & Schaie, 1981). The longitudinal markers included in this battery of necessity (i.e., for consistency across administration) employ the test booklet and answer sheet format used since the beginning of the SLS. All other forms use disposable booklets on which answers are marked directly (see Schaie, 1985). Brief descriptions of the ability factors, the longitudinal marker of each ability (contained in the basic test battery), and the additional measures are given below.
This is the ability to recognize and understand novel concepts or relationships; it involves the solution of logical problems--to foresee and plan. Thurstone (1949) proposed that persons with good reasoning ability could solve problems, foresee consequences, analyze situations on the basis of past experience, and make and carry out plans according to recognized facts.
PMA Reasoning (R). (Longitudinal marker) The study participant is shown a series of letters (e.g., a b x c d x e f x g h x). The letters in the row form a series based on one or more rules. The study participant is asked to discover the rule(s) and mark the letter that should come next in the series. In this case, the rule is that the normal alphabetical progression is interrupted with an x after every second letter. The solution would therefore be the letter i. There are 30 test items, with a time limit of 6 minutes.
ADEPT Letter Series (LS; Blieszner, Willis, & Baltes, 1981). This is a parallel form to the PMA Reasoning test. It has 20 test items, with a time limit of 4.5 minutes.
Word Series (WS). The study participant is shown a series of words (e.g., January, March, May) and is asked to identify the next word in the series. Positional patterns used in this test are identical to the PMA Reasoning test. There are 30 test items, with a time limit of 6 minutes.
Number Series (NS; T. G. Thurstone, 1962). The study participant is shown a series of numbers (e.g., 6, 11, 15, 18, 20) and is asked to identify the number that would continue the series. There are 20 items with a time limit of 4.5 minutes.
This is the ability to visualize and mentally manipulate spatial configurations in two or three dimensions, to maintain orientation with respect to spatial objects, and to perceive relationships among objects in space. This ability is important in tasks that require deducing one's physical orientation from a map or visualizing what objects would look like when assembled from pieces.
PMA Space (S). (Longitudinal marker) The study participant is shown an abstract figure and is asked to identify which of six other drawings represents the model in two-dimensional space. There are 20 test items, with a time limit of 5 minutes.
Object Rotation (OR; Quayhagen, 1979; Schaie, 1985). The study participant is shown a line drawing of a meaningful object (e.g., an umbrella) and is asked to identify which of six other drawings represent the model rotated in two-dimensional space. There are 20 test items, with a time limit of 5 minutes.
Alphanumeric Rotation (AR; Willis & Schaie, 1983). The study participant is shown a letter or number and is asked to identify which of six other drawings represents the model rotated in two-dimensional space. There are 20 test items, with a time limit of 5 minutes. Test stimuli in the Object and Alphanumeric rotation tests have the same angle of rotation as the abstract figure in the PMA Space test.
Cube Comparison (CC; Ekstrom et al., 1976). In each item, two drawings of a cube are presented; the study participant is asked to indicate whether the two drawings are of the same cube rotated in three- dimensional space. The Cube Comparison test has two parts, each with 15 items, and a time limit of 3 minutes.
This is the ability to understand numerical relationships, to work with figures, and to solve simple quantitative problems rapidly and accurately.
PMA Number (N). (Longitudinal marker) The study participant checks whether additions of simple sums shown are correct or incorrect. The test contains 60 items, with a time limit of 6 minutes.
Addition (AD; Ekstrom et al., 1976). This is a test of speed and accuracy in adding three single or two-digit numbers. The test has two parts, each with 20 items and a time limit of 3 minutes.
Subtraction and multiplication (SM; Ekstrom et al., 1976). This is a test of speed and accuracy with alternate rows of simple subtraction and multiplication problems. The test has two parts, each with 20 items and a time limit of 3 minutes.
This is the ability to understand ideas expressed in words. It indicates the range of a person's passive vocabulary used in activities where information is obtained by reading or listening.
PMA Verbal Meaning (V). (Longitudinal marker) A four-choice synonym test. This is a highly speeded test with significant loading on Perceptual Speed (Hertzog, 1989; Schaie, Willis, Jay, & Chipuer, 1989). The test has 50 items, with a time limit of 4 minutes.
ETS Vocabulary V-2 (VC; Ekstrom et al., 1976). A five-choice synonym test. The test has two parts, each with 18 items and a time limit of 4 min.
ETS Vocabulary V-4 (AVC; Ekstrom et al., 1976). A more advanced five-choice synonym test consisting mainly of difficult items. This test also has two parts, each with 18 items and a time limit of 4 min. Both ETS vocabulary tests are virtually unspeeded.
This ability is concerned with the verbal recall involved in writing and talking easily. It differs from verbal ability in that it focuses on the speed and ease with which words are used, rather than on the degree of under standing of verbal concepts.
PMA Word Fluency (W). (Longitudinal marker) The study participant recalls as many words as possible according to a lexical rule in a 5-minute period. No additional markers were included for this ability, because it appears to be factorially more complex than suggested by Thurstone's original work. The test is retained, however, because of the availability of extensive longitudinal data for this variable. In factor analytic work it has been shown to load on Verbal Memory and Verbal Ability (Schaie, Dutta, & Willis, 1991).
This is the ability to find figures, make comparisons and carry out other simple tasks involving visual perception with speed and accuracy.
Identical Pictures (IP; Ekstrom et al., 1976). (Longitudinal marker beginning in 1975) The study participant identifies which of five numbered shapes or pictures in a row is identical to the model at the left of the row. There are 50 items, with a time limit of 1.5 minutes.
Finding A's (FA; Ekstrom et al., 1976). (Longitudinal marker beginning in 1975. In each column of 40 words, the study participant must identify the 5 words containing the letter "a". There are 50 columns of numbers, and a time limit of 1.5 minutes.
Number Comparison (NC; Ekstrom et al., 1976). The study participant inspects pairs of multi-digit numbers and indicates whether the two numbers in each pair are the same or different. There are 40 items, with a time limit of 1.5 minutes.
This ability involves the memorization and recall of meaningful language units (Zelinski, Gilewski, & Schaie, 1993).
Immediate Recall (IR). Subjects study a list of 20 words for 3.5 minutes, they are then given an equal period of time to recall the words in any order.
Delayed Recall (DR). Subjects are asked to recall the same list of words as in Immediate Recall after an hour of other activities (other psychometric tests).
From the original five longitudinal markers, we have consistently derived and reported data on five linear composites. Both indexes were originally suggested by the Thurstones (1949). The first is an Index of Intellectual Ability (IQ), a composite measure likely to approximate a conventional deviation IQ, obtained by summing subtest scores weighted approximately inversely to their standard deviation of each test:
IQ = V + S + 2R + 2N + W
The second composite score is an Index of Educational Aptitude (EQ) suggested by T. G. Thurstone (1958) as the best predictor from the PMA test battery of performance in educational settings:
EQ = 2V + R
Measures of self-reported cognitive change
The PMA Retrospective Questionnaire (PMARQ; first used in 1984) is given immediately after the five basic longitudinal marker tests have been administered. Subjects are asked to rate whether they think their performance at the current testing session was the same, better, or worse then when they took the tests 7 years earlier. Data collected with this questionnaire show only a modest correlation between subject's estimate of change and magnitude of actual change in 1984 (Schaie, Willis, & O’Hanlon, 1994). The major function of this questionnaire, therefore, is to provide semi-projective data on the subjects' perception of changes in their abilities over time. The PMARQ is also used in the post-test phase of our training studies to obtain the participants' subjective rating of experienced training gain.
Measures of everyday problem solving
The Basic Skills Assessment test developed at the Educational Testing Service (1977) contains 65 items that simulate real life tasks. Examples of such tasks included in the test involve reading a bus schedule, identifying locations on a road map, interpreting a medicine bottle label, finding information in the yellow pages of the telephone book, and so on. In addition to a total score, this test can also be scored for four factor scales identified in an item factor analysis (Willis, Schaie, Kennett, Zuo, Intrieri, & Persaud (under review). This test was administered during the 1984 and 1991 testing waves.
The Everyday Problems Test (Willis, 1990). Is a more structured test that was developed so as to map on the instrumental activities of daily living (IADL). Twenty-one sets of stimuli, which involve printed materials, obtained from real life documents; charts and labels are presented without a time limit. Two multiple-choice questions are asked with respect to each stimulus. In addition to the total score, there are seven six-item sub-scales assessing everyday competence on the dimensions of medication use, shopping, telephone use, financial matters, household activities, meal preparation, and transportation. This test has been administered in the 1998 and 2005 testing waves.
Measures of cognitive style
The Test of Behavioral Rigidity (TBR; Schaie, 1955, 1960; Schaie & Parham, 1975) contains the following three subtests:
This test was adapted from Bernstein's (1924) study of quickness and intelligence and represents the Spearmanian, or "functional," approach to the study of preservation and rigidity. Participants copy a printed paragraph that contains some words starting with capital letters, others spelled entirely in capitals, and some starting with lower case letters, with the remaining letters in capitals. In the second half of the test, participants recopy the paragraph, substituting capitals for lower case letters and lower case letters for capitals. Two and a half minutes are allowed for each half of the test.
This test yields two scores: copying speed (Cap), the number of words correctly copied in the first half of the test; and instructional set flexibility (Cap-R), the latter score representing the ratio (rounded to integers) of the number of correctly copied words in the second series to those in the first series.
Opposites test. In this newly constructed test, following the work of Scheier and Ferguson (1952), three lists of simple words must be responded to by first giving antonyms, then synonyms, and finally antonyms or synonyms, depending on whether the stimulus word is printed in upper or lower case letters. Each list has 40 stimulus words and a time limit of 2 min.
The test yields three scores: an associational speed (Opp) score, which is the sum of correct responses in the first two lists; and two associational flexibility scores. For this purpose, List 3 is examined for responses that are incorrect, responses started incorrectly, and erasures. The first score (Opp-R1) is obtained by the formula:
Series 3 errors
100 - ------------------------- x 100
Series 3 total
The second score (Opp-R2) involves the formula:
Series 3 correct
----------------------------------------------- x 100
(1/2 (Series 1 correct + Series 2 correct))
Seventy-five true-or-false items include 22 modified flexibility-rigidity items (R scale) and 44 masking social responsibility items from the California Psychological Inventory (Gough 1957; Gough, McCloskey, & Meehl, 1952; Schaie, 1959b). Also included are 9 items (P scale) constructed by means of Guttman scaling of a preservative behavior scale first used by Lankes (1915).
The TBR yields factor scores for the latent dimensions of Psychomotor Speed, Motor-Cognitive Flexibility, and Attitudinal Flexibility. It also yields several personality trait scores (see below). The three factor scores are obtained by multiplying the standardized factor scores for the eight observed scores from the TBR subtests as follows:
MCF = .25 Cap-R + .35 Opp-R1 + .40 Opp-R2
AF = .50 R scale + .50 P scale
PS = .60 Cap + .40 Opp
For comparison across measures, all psychometric tests were standardized to T-scores with a mean of 50 and a standard deviation of 10, based on all data collected at first test.
Descriptions of lifestyles and demographic characteristics
The Life Complexity Inventory (LCI; Gribbin, Schaie, & Parham, 1980) provides information on subjects' demographic characteristics, activity patterns, work characteristics, continuing educational pursuits, and living arrangements. The LCI was initially administered by interviewers and then converted into a mail survey in 1974, and has been administered routinely (as a take-home task), since the fourth SLS cycle. Early analyses were based on the identification of eight item clusters in early work (Gribbin, Schaie, & Parham, 1980) for use in relating the LCI to the cognitive variables, these are:
1. Subjective dissatisfaction with life status
2. Social status
3. Noisy environment
4. Family dissolution
5. Disengagement from interaction with the environment
6. Semi-passive engagement with the environment
7. Maintenance of acculturation
8. Female homemaker characteristics.
Current scoring approaches are guided by results of a more recent factor analysis (O'Hanlon, 1993). The factor used in the more recent analyses represent the following eight constructs:
1. Social prestige
2. Demographic status
3. Leisure activities
4. Physical environment
5. Mobility characteristics
6. Intellectual environment
7. Social network
8. Work environment.
The leisure activities have also been factored and are scored as proportion of activity devoted to the following six types of activities:
1. Fitness activities
2. Educational activities
3. Social activities
4. Communicative activities
5. Solitary activities
6. Household chores.
Descriptions of health status
Health history abstracts. Health history data for the longitudinal study participants were obtained from time of entry into the study through 1998 for all participants remaining in the study and for those who dropped out for the 7 years following their last assessment, or until their death if the latter occurred earlier.
Health history data consist of the number of annual physician visits or hospital days by diagnosis (coded according to the International Classification of Diseases, ICDA, 8th edition until 1984; 9th edition thereafter). In addition, the number of continuous illness episodes per year are also coded.
Health histories were physically abstracted by medical librarians until 1991. Data thereafter come from the computerized HMO records.
Medication reports. Beginning with the sixth (1991) cycle, medication data have been collected by means of a brown bag procedure, in which subjects bring their current medications to the testing site, where the medication identifiers are recorded. Diseases for the treatment of which these medications are prescribed are identified using the procedure advocated by the American Society of Hospital Pharmacists (1985). In addition we were able to obtain complete computerized pharmacy record for the four-month window preceding the actual testing date for all subjects participating in the seventh (1998) cycle.
Identification of relatives with dementia. Beginning with the sixth cycle we asked all participants to list blood relatives who they thought had been diagnosed as suffering from Disease of the Alzheimer's Type (DAT). Information was also sought on whether such relatives were still living and, if dead, their age at death.
Blood samples. Since 1998 we have been able to obtain blood samples from most participants over age 60 within a one-month window of the psychological assessment. Data obtained from the blood samples consist of ApoE genotypes, a lipid profile, homocysteine and C-Reactive Protein. Blood cells have been cryopreserved for potential future genetic analyses.
Health behavior questionnaire (HBQ). An 85-item health behavior questionnaire covering preventive health behaviors and health practices was developed and first administered to participants in the sixth cycle and the first family study in 1993. The questionnaire continues to be administered in all subsequent data collections. The HBQ has been factored and represents seven clusters of health behavior, as well as a measure of subjectively reported health status.
Descriptions of the subjective environment
These data have been collected in the longitudinal study since the sixth (1991) cycle as well as in all family studies.
Family environment. The eight scales of the Family Environment Scale (Moos & Moos, 1986) were abbreviated to five items for each scale, and the individual items were converted into 5-point Likert scales. Items were edited to be suitable for inclusion in two versions of the instrument: (1) a form suitable for describing the perceived environment in the family of origin; (2) a form suitable for describing the perceived environment in the current family. For the latter, two versions were prepared: one suitable for individuals living in multi-member family settings and one for individuals currently living by themselves. For purposes of the latter form, "family" was defined as those individuals who the respondent felt were close to him or her and with whom a personal interaction occurred at least once every week.
The eight family environment scales are thought to assess the following dimensions:
* Cohesion. (Relationship) Example: "Family members really help one another."
* Expressivity. (Relationship) Example: "We tell each other about our personal problem."
* Conflict. (Relationship) Example: "Family members hardly ever lose their temper."
* Achievement Orientation. (Personal growth) Example: "We feel it is important to be the best at whatever we do."
* Intellectual--Cultural Orientation. (Personal growth) Example: "We often talk about political and social problems."
* Active--Recreational Orientation. (Personal growth) Example: "Friends often come over for dinner or to visit."
* Organization. (System maintenance) Example: "We are generally very neat and orderly."
* Control. (System Maintenance) Example: "There are set ways of doing things at home."
Work environment. In a manner similar to the family environment scales, three scales of the Work Environment Inventory (Moos, 1981) were also abbreviated to five items and converted to 5-point Likert scales. The content attributed to these dimensions is as follows.
1. Autonomy. The extent to which employees are encouraged to be self-sufficient and make their own decisions. Example: "You have a great deal of freedom to do as you like in your workplace."
2. Control. The extent to which management uses rules and pressure to keep employees under control. Example: "You are expected to follow set rules in doing your work."
3. Innovation. The degree of emphasis on variety, change, and new approaches. Example: "Your are encouraged to do your work in different ways."
Family contact. A 7-item (6-point Likert scale) form assesses the degree of actual contact between family members. Items inquire about the number of years family members have lived in the same household and the frequency of current personal contact, telephone contact, written contact, and contact through other informants.
Personality traits and attitudes
Social Responsibility (SR). The TBR Questionnaire was designed to include 44 masking items derived from the Social Responsibility scale of the California Psychological Inventory (CPI; Gough, 1957; Gough, McCloskey, & Meehl, 1952; Schaie, 1959b). The scale is of interest because it has allowed us to chronicle attitudinal shifts toward society over time (Schaie, 2005; Schaie & Parham, 1974) as well as attitudinal differences within families (Schaie, Plomin, Willis, Gruber-Baldini, & Dutta, 1992).
Derived Traits. A factor analysis of the 75 items contained in the TBR questionnaires collected during the first three study cycles resulted in the identification of 19 personality factors, several of which could be matched in content to at least one of the poles of the Cattell et al, 16-PF scale (Schaie & Parham, 1976). More recently we have replicated 13 of these factors for the entire database through the fifth SLS cycle (Maitland, Dutta, Schaie, & Willis, 1992; Willis, Schaie, & Maitland, 1992; see also Schaie, 2005, chapter 12).
The NEO Personality Questionnaire (Form R). This 240-item personality questionnaire representing the big 5 personality factors (Costa & McCrae, 1992) was administered by mail in 2001 to individuals participating in the 1996/97 family study and in the 1998 longitudinal cycle. The questionnaire was readministered as part of the 2004/05 family study and the 2005/06 eighth wave of the longitudinal study. The questionnaire measures the personality factors of neuroticism (N), extroversion (E), openness to experience (O), agreeableness (A), and conscientiousnes (C). Each of these factors is defined by a number of more specific traits or facets (Costa & McCrae, 1992).