A procedure for combining sample standardized mean differences and vote counts to estimate the population standardized mean difference in fixed event models.

Missing effect-size estimates pose a difficult problem in meta-analysis. Conventional procedures for dealing with this problem include discarding studies with missing estimates and imputing single values for missing estimates (e.g., 0, mean). An alternative procedure, which combines effect-size estimates and vote counts, is proposed for handling missing estimates. The combined estimator has several desirable features: (a) It uses all the information available from studies in a research synthesis, (b) it is consistent, (c) it is more efficient than other estimators, (d) it has known variance, and (e) it gives weight to all studies proportional to the Fisher information they provide. The combined procedure is the method of choice in a research synthesis when some studies do not provide enough information to compute effect-size estimates but do provide information about the direction or statistical significance of results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing squared multiple correlation coefficients: Examination of a confidence interval and a test significance.

I. Olkin and J. D. Finn (1995) presented 2 methods for comparing squared multiple correlation coefficients for 2 independent samples. In 1 method, the researcher constructs a confidence interval for the difference between 2 population squared coefficients; in the 2nd method, a Fisher-type transformation of the sample squared correlation coefficient is used to obtain a test statistic. Both methods are based on asymptotic theory and use approximations to the sampling variance. The approximations are incorrect when the population multiple correlation coefficient is zero. The 2 procedures were examined for equal and unequal population multiple correlation coefficients in combination with equal and unequal sample sizes. As expected, the procedures were inaccurate when the population multiple correlation coefficients were zero or very small and, in some conditions, were inaccurate when sample sizes and coefficients were unequal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bootstrapping to test for nonzero population correlation coefficients using univariate sampling.

This article proposes 2 new approaches to test a nonzero population correlation (ρ): the hypothesis-imposed univariate sampling bootstrap (HI) and the observed-imposed univariate sampling bootstrap (OI). The authors simulated correlated populations with various combinations of normal and skewed variates. With αset=.05, N≥10, and ρ≤0.4, empirical Type I error rates of the parametric r and the conventional bivariate sampling bootstrap reached .168 and .081, respectively, whereas the largest error rates of the HI and the OI were .079 and .062. On the basis of these results, the authors suggest that the OI is preferable in alpha control to parametric approaches if the researcher believes the population is nonnormal and wishes to test for nonzero ρs of moderate size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A goodness-of-fit approach to inference procedures for the kappa statistic: confidence interval construction, significance-testing and sample size estimation

We propose a new procedure for constructing a confidence interval about the kappa statistic in the case of two raters and a dichotomous outcome. The procedure is based on a chi-square goodness-of-fit test as applied to a model frequently used for clustered binary data. The procedure provides coverage levels that are accurate in samples of smaller size than those required for other procedures. The procedure also has use for significance-testing and the planning of corresponding sample size requirements.     

Testing the null hypothesis in meta-analysis: A comparison of combined probability and confidence interval procedures.

Combined significance tests (combined p values) and tests of the weighted mean effect size are used to combine information across studies in meta-analysis. A combined significance test (Stouffer test) is compared with a test based on the weighted mean effect size as tests of the same null hypothesis. The tests are compared analytically in the case in which the within-group variances are known and compared through large-sample theory in the more usual case in which the variances are unknown. Generalizations suggested are then explored through a simulation study. This work demonstrates that the test based on the average effect size is usually more powerful than the Stouffer test unless there is a substantial negative correlation between within-study sample size and effect size. Thus, the test based on the average effect size is generally preferable, and there is little reason to also calculate the Stouffer test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A pessimistic estimate of the time required for an eye to evolve

Theoretical considerations of eye design allow us to find routes along which the optical structures of eyes may have evolved. If selection constantly favours an increase in the amount of detectable spatial information, a light-sensitive patch will gradually turn into a focused lens eye through continuous small improvements of design. An upper limit for the number of generations required for the complete transformation can be calculated with a minimum of assumptions. Even with a consistently pessimistic approach the time required becomes amazingly short: only a few hundred thousand years.     

Determining sample size for a test of the equality of alpha coefficients when the number of part-tests is small.

In some measurement studies, the researcher seeks to compare the internal consistency reliability coefficients (α? and α?) of 2 rating scales or 2 observational techniques. In planning such studies, the investigator must determine the sample size (e.g., the number of participants or raters) that should be used if the power of the test of the null hypothesis is to be adequate. In this article, tables are derived that enable the researcher to determine what sample sizes are required to attain a specified power against a given alternative to the hypothesis of equality of 2 values of Cronbach's alpha coefficient. The tables cover situations in which either independent or dependent samples of participants or raters are used to estimate the reliability coefficients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some observations of the effects of intertrial interval and delay on delayed matching to sample in pigeons.

Accuracy of delayed matching to sample was studied in 12 Silver King pigeons at different combinations of length of intertrial interval (ITI) and length of delay. When ITI and delay were varied between sessions in Exps I and II, accuracy increased monotonically with ITI and decreased monotonically with delay. Evidence was found for constancy of performance at equivalent ratios of ITI to delay, and percentage of correct choices was linearly related to the log of this ratio. In Exps III and IV, ITI was manipulated as a within-sessions variable. In contrast to the effect of this variable when manipulated between sessions, accuracy improved only from the shortest interval to the next shortest interval and remained constant at all longer intervals. In Exp IV, it was found that performance improved as a direct function of the mean ITI for sessions and that this relation was not affected by the degree of ITI variability within sessions. Findings resemble the effects of temporal variables on autoshaping, and the possibility that some common processes are involved in delayed matching and autoshaping is discussed. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effectiveness of experimenter-provided and self-generated implementation intentions to reduce alcohol consumption in a sample of the general population: A randomized exploratory trial.

Objective: To test the effectiveness of implementation intentions to decrease alcohol consumption and control for possible demand characteristics by employing an active control condition and contrasting experimenter-provided with self-generated implementation intentions. Design: Two hundred forty-eight participants were randomly allocated to 1 of 4 conditions: questionnaire-only; questionnaire plus planning instruction; questionnaire, planning instruction plus experimenter-provided implementation intention; or questionnaire, planning instruction plus self-generated implementation intention. Main Outcome Measure: Alcohol intake. Results: There were clinically and statistically significant decreases in alcohol consumption in the 2 experimental conditions, but not in the 2 control conditions, F(3, 237) = 3.34, p p2 = .04. There were no significant differences between experimenter-provided and self-generated implementation intentions (p = .62). Compliance moderated the effects of self-generated implementation intentions only, such that alcohol intake only significantly decreased in participants who complied with the instructions, F(1, 52) = 4.20, p p2 = .07. However, simply choosing an experimenter-provided implementation intention was just as effective as writing it out in full, implying that implementation intentions work even with minimal information processing. Conclusion: The findings further support use of implementation intentions to protect against health risk behaviors and are congruent with laboratory research showing that implementation intentions are a case of strategic automaticity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simple device to obtain a pulsatile flow. Application to the vascular perfusion of dogs isolated intestinal segments

A simple device allowing a pulsatile flow to be obtained in isolated organ perfusion has been developed and applied to the vascular perfusion of isolated canine jejunal segments. The principle of the device consists of superimposing on a constant pressure produced by a roller pump, a pulsatile pressure of which the amplitude, frequency, and shape of the pulses can be adjusted separately and independently of the mean pressure value. The role of the arterial pulse in intestinal vascular perfusion has been studied by comparing the hemodynamic and metabolic behavior during alternate periods of pulsatile and nonpulsatile pumping. While no striking change in vascular resistance was observed, the O2 consumption was significantly increased under pulsatile flow. These results testify to better metabolic conditions and enhanced organ functions under pulsatile pumping and also argue for improved intestinal microcirculation despite the constancy of the vascular resistance.     

Description and validation of a procedure for the interpretation of an interest inventory score profile.

The rationale underlying a formal procedure to interpret interest inventory score profiles is discussed, and the procedure is described. I validated the proposed procedure by comparing its interpretation of the interests of 100 high school seniors and 50 young adults with the interpretations of 5 career counselors. The average agreement between the interpretation of the formal procedure and that of the counselors (about 90%) was almost as high as the agreement among the career counselors themselves (about 91%). The implications of this result are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative power of moderated multiple regression and the comparison of subgroup correlation coefficients for detecting moderating effects.

A Monte Carlo simulation assessed the relative power of 2 techniques that are commonly used to test for moderating effects. 500 samples were drawn from simulation-based populations for each of 81 conditions in a design that varied sample size, the reliabilities of 2 predictor variables (1 of which was the moderator variable), and the magnitude of the moderating effect. The null hypothesis of no interaction effect was tested by using moderated multiple regression (MMR). Each sample was then successively polychotomized into 2, 3, 4, 6, and 8 subgroups, and the equality of the subgroup-based correlation coefficients (SCC) was tested. Results show MMR to be more powerful than the SCC strategy for virtually all of the 81 conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A canonical correlation analysis of the Wechsler Intelligence Scale for Children—Revised and the Woodcock-Johnson Tests of Cognitive Ability in a sample referred for suspected learning disabilities.

Examined the degree of overlap between the WISC—R and the Woodcock-Johnson Tests of Cognitive Ability (WJTCA) from the Woodcock-Johnson Psycho-Educational Battery in 152 Ss (aged 7 yrs 4 mo to 12 yrs 10 mo) referred for evaluation because of suspected learning disabilities (LD). Analysis yielded 3 significant canonical correlations. The redundancy index showed that approximately 28.6% of the WJTCA subtest variance was predictable from the linear combination of the WISC—R subtests, and approximately 32.7% of the WISC—R subtest variance was predictable from the WJTCA subtests. Analysis of the structure correlations showed that the 1st canonical variates shared a general intelligence factor, the 2nd a perceptual speed factor, and the 3rd a numerical-memory factor. It is suggested that, if these findings are substantiated with a larger sample, the mean-score discrepancy previously found between the WJTCA and the WISC—R for children suspected of having LD is attributable to unique factor structures. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing patients' predicted test scores from a regression equation with their obtained scores: A significance test and point estimate of abnormality with accompanying confidence limits.

In contrast to the standard use of regression, in which an individual's score on the dependent variable is unknown, neuropsychologists are often interested in comparing a predicted score with a known obtained score. Existing inferential methods use the standard error for a new case (sN+1) to provide confidence limits on a predicted score and hence are tailored to the standard usage. However, sN+1 can be used to test whether the discrepancy between a patient's predicted and obtained scores was drawn from the distribution of discrepancies in a control population. This method simultaneously provides a point estimate of the percentage of the control population that would exhibit a larger discrepancy. A method for obtaining confidence limits on this percentage is also developed. These methods can be used with existing regression equations and are particularly useful when the sample used to generate a regression equation is modest in size. Monte Carlo simulations confirm the validity of the methods, and computer programs that implement them are described and made available. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A score method of constructing asymmetric confidence intervals for the mean of a rating scale item.

This article presents a generalization of the Score method of constructing confidence intervals for the population proportion (E. B. Wilson, 1927) to the case of the population mean of a rating scale item. A simulation study was conducted to assess the properties of the Score confidence interval in relation to the traditional Wald (A. Wald, 1943) confidence interval under a variety of conditions, including sample size, number of response options, extremeness of the population mean, and kurtosis of the response distribution. The results of the simulation study indicated that the Score interval usually outperformed the Wald interval, suggesting that the Score interval is a viable method of constructing confidence intervals for the population mean of a rating scale item. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representativeness of the Wade and Baker sample: A reply to Garfield.

Responds to S. L. Garfield's (1978) comments on a previous study by T. C. Wade and T. B. Baker (see record 1978-20152-001) on clinical psychologists' opinions and use of psychological tests. Discrepancies between the study and Garfield's work may have resulted from differences in the questionnaire format, as the findings are remarkably similar. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of a densitometric method for the determination of cephalexin as an alternative to the standard HPLC procedure

A HPTLC-densitometric method was developed in order to obtain a reliable procedure for routine analysis of cephalexin in pharmaceutical formulations. Optimization of TLC conditions for the densitometric scanning was reached by eluting HPTLC silica gel plates in an horizontal developing chamber. Quantitation of cephalexin was performed in single beam reflectance mode by using a computer-controlled densitometric scanner and applying a five-point calibration. A linear regression has been found in the 200-1000 ng range. The setup method is precise, reproducible and accurate. Recovery was also assessed by comparison with the HPLC USP XXIII alternate method. In this case HPTLC-densitometry appears worth of consideration as being relatively inexpensive and time-saving (up to 12 samples can be determined simultaneously in less than 15 min with a solvent consumption of about 15 ml). The results suggest that the proposed method may be used in place of HPLC for the routine quantitation of cephalexin in both pure and dosage forms.     

Behavior therapy for Tourette's disorder: Utilization in a community sample and an emerging area of practice for psychologists.

The current article describes the phenomenology and empirically supported treatments for Tourette's disorder (TD) and presents data on treatment utilization from two separate national surveys of adults with TD (N = 672) and parents of children with TD (N = 740). Despite a wealth of empirical evidence demonstrating its effectiveness, results suggest that most people with TD do not receive behavior therapy for the condition. Reasons for this include a lack of information about the disorder among consumers and providers, a shortage of providers trained in the treatment, and concern about possible negative effects of behavioral treatment. The article concludes with a discussion about dissemination efforts aimed at making behavior therapy more widely available to children and adults with chronic tics and a review of beliefs about the negative effects of behavior therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)