Multivariate Aligned Rank Test for Interactions in Multiple Group Repeated Measures Designs

2002 ◽  
Vol 37 (2) ◽  
pp. 197-226 ◽  
Author(s):  
T. Mark Beasley
Keyword(s):  
Repeated Measures ◽  
Rank Test ◽  
Multiple Group ◽  
Repeated Measures Designs ◽  
Aligned Rank

Nonparametric Tests for Analyzing Interactions Among Intra-Block Ranks in Multiple Group Repeated Measures Designs

2000 ◽  
Vol 25 (1) ◽  
pp. 20-59 ◽  
Author(s):  
T. Mark Beasley
Keyword(s):  
Repeated Measures ◽  
Profile Analysis ◽  
Nonparametric Tests ◽  
Covariance Matrices ◽  
Statistical Properties ◽  
Multivariate Approach ◽  
Omnibus Test ◽  
Multiple Group ◽  
Multiple Groups ◽  
Repeated Measures Designs

This study developed an extension of the Hollander and Sethuraman (1978) statistic (B2 ) for testing discordance among intra-block rankings of K elements for multiple groups (J ≥ 2) of raters. B2 was demonstrated to be equivalent to the Pillai-Bartlett trace (V ) from a multivariate profile analysis performed on the ranks such that B2 = V (N - 1) Results confirmed the utility of B2 as an omnibus test of interaction (i.e., discordance) among intra-block ranks and demonstrated that it was more powerful than the multivariate approach to ranked data suggested by Serlin and Marascuilo (1983) . An extension of the Friedman (1937) two-way ANOVA for intra-block ranks was also developed. The adequacy of these procedures for testing interactions in multiple group repeated measures designs was investigated. The Friedman model demonstrated adequate statistical properties only when covariance matrices were spherical. Results also demonstrated that the Hollander-Sethuraman model was useful in testing interaction contrasts.

Increasing Precision without Altering Treatment Effects: Repeated Measures Designs in Survey Experiments

2021 ◽  
pp. 1-18
Author(s):  
SCOTT CLIFFORD ◽  
GEOFFREY SHEAGLEY ◽  
SPENCER PISTON
Keyword(s):  
Treatment Effect ◽  
Repeated Measures ◽  
Treatment Effects ◽  
Repeated Measurements ◽  
Experimental Designs ◽  
Treatment Effect Size ◽  
Standard Design ◽  
Survey Experiments ◽  
Repeated Measures Designs ◽  
Alternative Designs

The use of survey experiments has surged in political science. The most common design is the between-subjects design in which the outcome is only measured posttreatment. This design relies heavily on recruiting a large number of subjects to precisely estimate treatment effects. Alternative designs that involve repeated measurements of the dependent variable promise greater precision, but they are rarely used out of fears that these designs will yield different results than a standard design (e.g., due to consistency pressures). Across six studies, we assess this conventional wisdom by testing experimental designs against each other. Contrary to common fears, repeated measures designs tend to yield the same results as more common designs while substantially increasing precision. These designs also offer new insights into treatment effect size and heterogeneity. We conclude by encouraging researchers to adopt repeated measures designs and providing guidelines for when and how to use them.

Dilutional Acidosis following Hetastarch or Albumin in Healthy Volunteers

2000 ◽  
Vol 93 (5) ◽  
pp. 1184-1187 ◽  
Author(s):  
Jonathan H. Waters ◽  
Clifford A. Bernstein
Keyword(s):  
Healthy Volunteers ◽  
Repeated Measures ◽  
Base Excess ◽  
Rank Test ◽  
Albumin Concentration ◽  
Acid Base Balance ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
The Impact

Background The intent of this study was to evaluate the impact of the commonly used colloids-hetastarch and albumin-on in vivo acid-base balance. From this evaluation, a better understanding of the mechanism of dilutional acidosis was expected. Methods In a prospective, randomized fashion, 11 healthy volunteers were administered 15 ml/kg hetastarch solution, 6%, or 15 ml/kg albumin, 5%, intravenously over 30 min. Four weeks later, the study subjects were administered the other colloid. Arterial blood gas and electrolyte parameters were measured at baseline and at 30, 60, 90, 120, 210, and 300 min after colloid administration. Pre- and postlaboratory values were compared within groups using a paired t test and a Wilcoxon signed rank test and between groups using repeated-measures analysis of variance and a Wilcoxon rank sum test. Results Thirty min after infusion, subjects who were administered hetastarch showed statistically significant changes (P < 0.05) in base excess (from 2.5 +/- 0.9 mEq/l to 0.7 +/- 1.1 mEq/l), HCO3- concentration (from 27 +/- 1.0 mEq/l to 25 +/- 1.3 mEq/l), Cl- concentration (from 108 +/- 2 mEq/l to 112 +/- 2 mEq/l), albumin concentration (from 4.4 +/- 0.2 g/dl to 3.5 +/- 0.5 g/dl), and arterial carbon dioxide tension (Paco2; from 40.8 +/- 2.3 mmHg to 39. 2 +/- 3.2 mmHg), whereas only the albumin concentration (from 4.4 +/- 0.2 g/dl to 4.8 +/- 0.6 g/dl) changed significantly in the albumin-treated group. Conclusions Decreases in base excess were observed for 210 min after hetastarch administration but not after albumin. The mechanism for this difference is discussed.

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