caa a22 4500 388079770 CHVBK 20180307125210.0 cr unu---uuuuu 161130e199903 xx s 000 0 eng 10.2307/2585759 doi S0003055400216602 pii (NATIONALLICENCE)cambridge-10.2307/2585759 Comparing Interest Group Scores across Time and Chambers: Adjusted ADA Scores for the U.S. Congress [Elektronische Daten] Interest group ratings are widely used in studies of legislative behavior. Since the set of votes used is not constant over time and across chambers, the scales underlying the scores can shift and stretch. We introduce an econometric model that corrects the problem. Specifically, we derive an index, much like an inflation index for consumer prices, that allows one to make intertemporal and interchamber comparisons of interest group ratings. The adjusted scores for the ADA show a strong liberal trend in the average member of Congress during 1947-94, followed by a conservative reversal. A nonparametric test using ADA and ACU scores demonstrates the validity of adjusted scores and the invalidity of nominal scores for intertemporal and interchamber comparisons. Using two studies (Levitt 1996; Shipan and Lowry 1997) we illustrate that the choice of adjusted versus nominal scores may greatly affect substantive conclusions of researchers. Copyright © American Political Science Association 1999 Groseclose Tim Stanford University Levitt Steven D. University of Chicago Snyder James M. Massachusetts Institute of Technology American Political Science Review Cambridge University Press 93/1(1999-03), 33-50 0003-0554 93:1<33 1999 93 PSR https://doi.org/10.2307/2585759 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.2307/2585759 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Groseclose Tim Stanford University NATIONALLICENCE 700 1- Levitt Steven D. University of Chicago NATIONALLICENCE 700 1- Snyder James M. Massachusetts Institute of Technology NATIONALLICENCE 773 0- American Political Science Review Cambridge University Press 93/1(1999-03), 33-50 0003-0554 93:1<33 1999 93 PSR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge