How to measure national stereotypes?
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Character↗
Biomedical subjects
Robert E McGrath
Publications and source records attributed to Robert E McGrath.
When effect sizes disagree: the case of r and d.
The increased use of effect sizes in single studies and meta-analyses raises new questions about statistical inference. Choice of an effect-size index can have a substantial impact on the interpretation of findings. The authors demonstrate the issue by focusing on two popular effect-size measures, the correlation coefficient and the standardized mean difference (e.g., Cohen's d or Hedges's g), both of which can be used when one variable is dichotomous and the other is quantitative. Although the indices are often practically interchangeable, differences in sensitivity to the base rate or variance of the dichotomous variable can alter conclusions about the magnitude of an effect depending on which statistic is used. Because neither statistic is universally superior, researchers should explicitly consider the importance of base rates to formulate correct inferences and justify the selection of a primary effect-size statistic.
Data Interpretation, Statistical↗
Field reliability of comprehensive system scoring in an adolescent inpatient sample.
The extent to which the Comprehensive System for the Rorschach is reliably scored has been a topic of some controversy. Although several studies have concluded it can be scored reliably in research settings, little is known about its reliability in field settings. This study evaluated the reliability of both response-level codes and protocol-level scores among 84 adolescent psychiatric inpatients in a clinical setting. Rorschachs were originally administered and scored for clinical purposes. Among response codes, 87% demonstrated acceptable reliability(> .60), and most coefficients exceeded .80. Results were similar for protocol-level scores, with only one score demonstrating less than adequate reliability. The findings are consistent with previous evidence, indicating reliable scoring is possible even in field settings.
Adolescent↗
Conceptual complexity and construct validity.
Despite a century of methodological and conceptual advances in the technology of psychosocial measurement, poor correspondence between indicators and the constructs they are intended to represent remains a limiting factor to the accumulation of scientific knowledge. Longstanding conventions in measurement may contribute to the failure to develop optimal criteria. These conventions include the focus on complex over simple constructs and the use of multi-item measures of disparate content to represent those constructs. Several arguments suggest that such a measurement model compromises the potential for developing measures that accurately reflect psychosocial phenomena. The article concludes with some preliminary suggestions concerning an alternative model that may address this construct validity problem more effectively.
Humans↗
Efficacy of modified constraint-induced movement therapy in chronic stroke: a single-blinded randomized controlled trial.
OBJECTIVE: To determine efficacy of a modified constraint-induced movement therapy (mCIMT) protocol for patients with chronic stroke. DESIGN: Multiple-baseline, pre-post, single-blinded randomized controlled trial. SETTING: Outpatient clinic. PARTICIPANTS: Seventeen patients who experienced stroke more than 1 year before study entry and who had upper-limb hemiparesis and learned nonuse. INTERVENTION: Seven patients participated in structured therapy sessions emphasizing more affected arm use in valued activities, 3 times a week for 10 weeks. Their less affected arms were also restrained 5d/wk for 5 hours (mCIMT). Four patients received regular therapy with similar contact time to mCIMT. Six patients received no therapy (control). MAIN OUTCOME MEASURES: The Fugl-Meyer Assessment of Motor Recovery (FMA), Action Research Arm (ARA) Test, and Motor Activity Log (MAL). RESULTS: The mCIMT patients exhibited greater motor changes on the FMA and ARA (18.4, 11.4) than regular therapy (6.0, 7.1) or control (-2.9, -4.5). Statistical analyses showed significant differences in motor improvement on the FMA (F(2,12)=11.2, P=.002) and the ARA (F(2,12)=14.0, P=.001). Post hoc analyses showed that, when pretreatment motor differences are controlled, mCIMT resulted in substantially higher posttreatment FMA and ARA scores. Amount and quality of arm use, measured by the MAL, improved only in mCIMT patients. CONCLUSIONS: mCIMT may be an efficacious method of improving function and use of the more affected arms of chronic stroke patients. Findings further affirm that repeated, task-specific practice is critical to reacquisition of function, whereas practice schedule intensity is less critical.
Adult↗
Saving our psychosocial souls.
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Drug Prescriptions↗
The making of meaning: comments on Hofstee and Ten Berge.
Hofstee and Ten Berge (2004/this issue) outline a method of scale transformation that places scores on a common absolute scale. This contrasts with traditional relative methods of transformation, which involve scaling in relation to a sample mean. Their primary intention seems to be to produce a scale that is intrinsically meaningful. This issue of scale meaning is discussed in some detail, including reference to an alternate approach to absolute scaling offered by Cohen, Cohen, Aiken, and West (1999). Ultimately, neither approach to absolute scaling seems completely satisfactory as a resolution to this problem. It is suggested that the lack of meaning inherent to many psychosocial measures is a natural product of traditional aggregative practices in scale development and may be invulnerable to statistical correction.
Humans↗
Mental and physical practice schedules in acquisition and retention of novel timing skills .
Research has indicated that random physical practice of a motor skill enhances effects of long-term learning more than blocked practice. Moreover, the use of mental rehearsal coupled with physical practice has been shown to accelerate motor skill acquisition in many different contexts and is better than no practice at all. Others have found that some mental rehearsal strategies are better than others for maximizing performance. This study examined how combinations of mental and physical practice schedules affected the learning of a coincidence timing task. 30 college students were randomly assigned to one of four treatment groups involving combinations of imagery and physical practice. Three tasks were utilized, each involving a particular speed (slow, medium, fast) on the Bassin Anticipation Timer. Conclusions were based on a three-way analysis of variance, using type of mental practice, type of physical practice, and sex as between-group factors, conducted separately for acquisition and retention trials. Type of physical practice was significantly related to performance. On the acquisition trials, random practice was associated with larger mean errors than blocked practice; however, the reverse was true for retention trials. There was no significant effect of type of mental practice in either the acquisition or retention phase. Sex was significantly related to performance for the retention trials only, where the 15 men made smaller errors than the 15 women.
Adult↗
Development of a short form for the MMPI-2 based on scale elevation congruence.
The length of the Minnesota Multiphasic Personality Inventory (MMPI) is often considered a barrier to its use, leading to the development of short forms. Two methods of abbreviating the revised MMPI have now been developed. One agrees poorly with the long form in terms of which scales are elevated. The second ensures perfect congruence in which scales are elevated but requires computer administration. This article describes the development of a short form representing a compromise approach. The short form was derived using 800 psychiatric inpatients and cross-validated with samples of 658 inpatients and 266 outpatients. It is briefer than the computerized short form but does not achieve perfect congruence with the full inventory. It is longer than earlier noncomputerized short forms but demonstrates greater scale elevation congruence with the full inventory and allows estimates of more scales. The short form offers a reasonable alternative when the full inventory is impractical.
Adult↗
A comparison of the PAI and MMPI-2 as predictors of faking bad in college students.
Both the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher et al., 2001) and Personality Assessment Inventory (PAI; Morey, 1991) offer a large set of scales devoted to the identification of response styles. This study directly compared the effectiveness of the 2 inventories as indicators of overreporting. The 2 measures were administered to 52 college students instructed to fake bad under conditions describing either a forensic (n = 24) or psychiatric (n = 28) setting as well as to 432 psychiatric patients. Results indicated that the MMPI-2 F - K index and Fp Scale were the best single indicators of a faking bad response style and that the MMPI-2 scales were the better indicators as a set. However, the PAI scales demonstrated a significant level of incremental validity over the MMPI-2 indicators in every analysis conducted. The findings suggest that either inventory offers an effective approach to the detection of overreporting, and administering both inventories can enhance the accuracy of prediction further.
Adult↗
Enhancing accuracy in observational test scoring: the comprehensive system as a case example.
Inaccuracies in administration and scoring can potentially compromise the validity of any standardized psychosocial measure. The threat is particularly pertinent to methods involving behavioral observation, a category that includes many intelligence tests, neuropsychological measures, personality assessment instruments, and diagnostic procedures. Despite evidence and conjecture that errors in testing procedure are common for at least some of these measures and that these errors are often severe enough to influence interpretation, the topic has received relatively little attention. In particular, the absence of any safeguard against inaccurate test use in clinical situations can put the respondent at risk and violates ethical standards for the use of tests. In this article, I review some issues surrounding accuracy in testing procedures, including a discussion of what is known about the problem, an evaluation of several approaches to improving testing practices, and a review of recommendations for the statistical evaluation of rater accuracy. In this article, I use the Rorschach Comprehensive System (Exner, 1993) to demonstrate the concepts discussed.
Ethics, Professional↗
Incremental validity of selected MMPI-A content scales in an inpatient setting.
To date, relatively few studies have been published evaluating the validity or incremental validity of the content scales from the adolescent version of the Minnesota Multiphasic Personality Inventory (MMPI-A; J. N. Butcher et al., 1992). A sample of 629 psychiatric inpatient adolescents who had completed the MMPI-A was used to evaluate the ability of selected clinical and content scales to predict conceptually related clinical variables. Criteria were based on clinician ratings, admission and discharge diagnoses, and chart reviews. Results from hierarchical multiple and logistic regression analyses indicated the content scales offered incremental validity over the clinical scales and supported the use of the content scales as an adjunct to the traditional clinical scales.
Adolescent↗
MMPI-A structural summary variables: prevalence and correlates in an adolescent inpatient psychiatric sample.
This study examined the prevalence and correlates of Archer and Krishnamurthy's MMPI-A Structural Summary (SS) dimensions in a sample of 632 adolescent psychiatric inpatients through a series of correlational analyses. These analyses examined the relationship between factor dimensions and categorically defined dimension elevations and external criterion measures that included chart review data, therapist ratings, chart diagnoses, and cognitive test performance. The SS dimensions provided additional interpretive yield for some within-normal-limits profiles. An examination of the pattern of correlations revealed small to moderate relationships between all SS variables and external criterion measures.
Adolescent↗
A comparison of MMPI-2 high-point coding strategies.
High-point coding refers to the popular practice of classifying Minnesota Multiphasic Personality Inventory (Hathaway & McKinley, 1983) profiles based on which clinical scales are the most elevated. A previous review of high-point code studies (McGrath & Ingersoll, 1999a) noted marked discrepancies across studies in the rules used to define high-point codes. This study was conducted to evaluate the costs and benefits of different strategies for high-point coding. The impact of 4 rules for high-point coding on effect sizes and group sizes was evaluated. The 4 rules included requiring a minimum elevation, excluding potentially invalid protocols, restricting coding to well-defined codes, and replacing the lower scale in infrequently occurring codes with the next most elevated scale. The evidence supported the clinical utility of requiring a minimum elevation for code scales. The results were more equivocal concerning the value of well-defined coding and for not replacing the lower scale in infrequent codes. Results were surprisingly negative concerning the utility of excluding potentially invalid protocols, suggesting that guidelines developed in situations in which there is a clear motivation to distort results may not generalize to other settings.
Adult↗