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The article presents a section of abstracts relating to computers, including "A Program for the Estimation of Internal Consistency of Composites with Congeneric Measurement Properties," by Erich A. Joachimsthaler, Lane Curtis, and Ronald E. Michaels, "An SAS Program to Test the Multivariate General Linear Hypothesis," by Linda Weiser Freidman and Hershey H. Friedman, and "A Program System to Examine the Order of Individual Brand Choice Processes," by Alfred Taudes and Udo Wagner.

Purpose: To quantify the influence of spectral domain optical coherence tomography (SDOCT) on decision-making in patients with suspected glaucoma. Methods: A prospective cross-sectional study involving 40 eyes of 20 patients referred by community optometrists due to suspected glaucoma. All patients had disc photographs and standard automated perimetry (SAP), and results were presented to 13 ophthalmologists who estimated pre-test probability of glaucoma (0–100%) for a total of 520 observations. Ophthalmologists were then permitted to modify probabilities of disease based on SDOCT retinal nerve fiber layer (RNFL) measurements (post-test probability). The effect of information from SDOCT on decision to treat, monitor, or discharge was assessed. Agreement among graders was assessed using intraclass correlation coefficients (ICC) and correlated component regression (CCR) was used to identify variables influencing management decisions. Results: Patients had an average age of 69.0 ± 10.1 years, SAP mean deviation of 2.71 ± 3.13 dB, and RNFL thickness of 86.2 ± 16.7 μm. Average pre-test probability of glaucoma was 37.0 ± 33.6% with SDOCT resulting in a 13.3 ± 18.1% change in estimated probability. Incorporating information from SDOCT improved agreement regarding probability of glaucoma (ICC = 0.50 (95% CI 0.38 to 0.64) without SDOCT versus 0.64 (95% CI 0.52 to 0.76) with SDOCT). SDOCT led to a change from decision to “treat or monitor” to “discharge” in 22 of 520 cases and a change from “discharge” to “treat or monitor” in 11 of 520 cases. Pre-test probability and RNFL thickness were predictors of post-test probability of glaucoma, contributing 69 and 31% of the variance in post-test probability, respectively. Conclusions: Information from SDOCT altered estimated probability of glaucoma and improved agreement among clinicians in those suspected of having the disease. [ABSTRACT FROM PUBLISHER]

The traditional approach for partialing out the effects of confounding factors in a non equivalent control group situation is to calculate a partial correlation coefficient or a (partial) regression coefficient controlling for one or more "covariates." Since the covariates generally are imperfect measures of the factors, this procedure will typically yield biased estimates of effect. An alternative approach, which allows for the presence of measurement error, is discussed and applied to some data from the original Head Start evaluation. Contrary to the original analysis, which found the Head Start program to be totally ineffective, the alternative approach yields small positive estimates of effect. The resulting model is conceptually feasible and fits the data well. However, it is only one of many possible causal models which could have been formulated. Guidelines are needed for building causal models in the evaluation research framework when little is known a priori regarding the causal relationships. [ABSTRACT FROM PUBLISHER]