Title

respdiff -- Generating response differentiation indices

Syntax

respdiff newvar = fcn(varlist) [if exp] [in range]

where fcn specifies the response differentiation index that is
computed based on the variables in varlist, and where fcn is

cv(varlist)

It creates the coefficient of variation CV for each row r of the data set
(e.g., survey respondents) over the n variables in varlist,
ignoring missing values. Technically, CV_r is computed as the standard deviation
of responses s_r divided by the mean of the responses x-bar_r
(see below for details on the computation of the standard deviation s_r).

nondiff(varlist)

It creates a binary variable inicating whether rows r
of the data set have the same value in the n variables in varlist (i.e.,
non-differentiated response patterns), ignoring missing values. Technically,
a non-differentiated response pattern is equivalent to a standard deviation
s_r = 0 (see below for details on the computation of the standard deviation
s_r).

sd(varlist)

It creates the standard deviation s for each row r of the data set (e.g., survey respondents)
over the n variables in varlist, ignoring missing values. The standard
deviation s_r equals the square root of the sum of the squared deviations
of the individual responses to the variables x_ri from the mean of the responses
to the variables x-bar_r divided by the number of variables n_r.

stdsd(varlist)

It creates the z-standardized standard deviation for each row of the data set
s_r for the n variables in varlist, ignoring missing values.

Description

The respdiff command enables users to generate several indices
of response differentiation for each row r of the data set over the n
variables in varlist, ignoring missing values (i.e., system missing values
and numeric values that have been changed to missing values using
the mvdecode command).

Theoretical background: Research in survey methodology has provided ample
evidence that survey respondents differ in the extent to which they differentiate
their answers to survey questions (Krosnick 1991). With respect to this finding,
the theory of survey satisficing proposes that under certain
conditions respondents might select a somehow reasonable response option for the
first item in a set of question items, and rate all (or almost all) remaining
items with the exactly same response value (Krosnick 1991).
In survey methodology, this response pattern is usually referred to as response
non-differentiation (e.g., Krosnick and Alwin 1988, Krosnick 1991)
or straightlining (e.g., Couper et al. 2013). The respdiff command enables
users to generate several indices of response differentiation. While the function
nondiff creates a binary indicator for non-differentiated responses, the
remaining functions (i.e., the (z-standardized) standard deviation of responses,
and the coefficient of variation) provide measures of the extent to which each
respondent provided differentiated responses to survey questions.

Examples

Generating a binary variable that indicates whether respondents provided
non-differentiated responses to the variables v1a through v1d.

. respdiff v1_nondiff = nondiff(v1a v1b v1c v1d)

Generating the standard deviation of the responses over the variables
v1_1 through v1_5.

. respdiff v1_sd = sd(v1_1 v1_2 v1_3 v1_4 v1_5)

Generating the coefficient of variation for the variables
q11a through q11e.

. respdiff q11_cv = cv(q11a q11b q11c q11d q11e)

Author

Joss Roßmann, GESIS - Leibniz Institute for the Social Sciences, joss.rossmann@gesis.org

Copyright (C) 2017 Joss Roßmann

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details <http://www.gnu.org/licenses/>.

Recommended citation (APA Style, 6th ed.):

Roßmann, J. (2017). RESPDIFF: Stata module for generating
response differentiation indices (Version: 1.0)
[Computer Software]. Chestnut Hill, MA: Boston College.

References

Couper, M. P., Tourangeau, R., Conrad, F. G., & Zhang, C. (2013).
The Design of Grids in Web Surveys.
Social Science Computer Review, 31(3), 322-345.

Krosnick, J. A. (1991). Response Strategies for Coping with the
Cognitive Demands of Attitude Measures in Surveys.
Applied Cognitive Psychology, 5(3), 213-236.

Krosnick, J. A., & Alwin, D. F. (1988). A Test of the Form-Resistant
Correlation Hypothesis. Ratings, Rankings, and the Measurement of Values.
Public Opinion Quarterly, 52(4), 526-538.