Placebo Statements in List Experiments

13 Pages Posted: 11 Jun 2019

See all articles by Guillem Riambau

Guillem Riambau

University of Barcelona

Kai Ostwald

University of British Columbia (UBC)

Date Written: May 26, 2019

Abstract

List experiments are a widely used survey technique for estimating the prevalence of socially sensitive attitudes or behaviors. Their design, however, makes them vulnerable to bias: because treatment group respondents see a greater number of items (J+1) than control group respondents (J), the treatment group mean may be mechanically inflated due simply to the greater number of items. The few previous studies that directly examine this do not arrive at definitive conclusions. We find clear evidence of inflation in an original dataset, though only among respondents with low educational attainment. Furthermore, we use available data from previous studies and find similar heterogeneous patterns. The evidence of heterogeneous effects has implications for the interpretation of previous research using list experiments, especially in developing world contexts. We recommend a simple solution: using a necessarily false placebo statement for the control group equalizes list lengths, thereby protecting against mechanical inflation without imposing costs or altering interpretations.

Keywords: List experiment, item count technique, survey design, placebo statement, satisficing, social desirability bias

Suggested Citation

Riambau, Guillem and Ostwald, Kai, Placebo Statements in List Experiments (May 26, 2019). Available at SSRN: https://ssrn.com/abstract=3394417 or http://dx.doi.org/10.2139/ssrn.3394417

Guillem Riambau (Contact Author)

University of Barcelona ( email )

Gran Via de les Corts Catalanes, 585
Barcelona, 08007
Spain

Kai Ostwald

University of British Columbia (UBC) ( email )

1855 West Mall
Vancouver, British Columbia BC V6T 1Z4
Canada

HOME PAGE: http://www.kaiostwald.me

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