Calculating Ideological Distance
Arguments
- df
data frame to read in. This should be an adapted version of the
Ideologydata set provided in the package. The adapted version should include an outcome variable measuring the policy adoption of choice.- id
the grouping variable, usually states
- ideology
the state's ideology score variable (either state or citizen ideology) in a given year. These data come from Richard C. Fording (https://rcfording.com/state-ideology-data/) as used in Berry et al. (1998), and are measured, for each state, from 1960 to 2018.
- time
the time variable, at which the ideology score is measured. These data come from Richard C. Fording (https://rcfording.com/state-ideology-data/) as used in Berry et al. (1998), and are measured, for each state, from 1960 to 2018.
- adoption
binary, user-defined measure of policy adoption in a state in a given year.
0equates to policy not adopted in the year, for the state,1equates to policy is adopted in the year, for the state – a value of1should only exist for a state in the year it was adopted (e.g. not every year thereafter). The example below relies on ERA ratification data from Soule and King (2006), but the user should include the measure of adoption of their choice.
Value
This function updates the data frame with a new variable capturing the ideological distance score.
References
Grossback, Lawrence J., Nicholson-Crotty, Sean, and
Peterson, David A.M.
(2004) 'Ideology and Learning in Policy Diffusion.'
American Politics Research 32:521-545.
doi:10.1177/1532673X04263801
.
Cruz-Aceves, Victor D., and Mallinson, Daniel J.
(2019) 'Clarifying the Measurement of Relative Ideology
in Policy Diffusion Research.'
State and Local Government Review 51:179-186.
doi:10.1177/0160323X20902818
.
Berry, William D., Ringquist, Evan J., Fording, Richard C.,
and Hanson, Russell L.
(1998) 'Measuring Citizen and Government Ideology
in the American States, 1960-93.'
American Journal of Political Science 42:327-348.
doi:10.2307/2991759
.
Soule, Sarah A., and King, Brayden G.
(2006) 'The Stages of the Policy Process
and the Equal Rights Amendment, 1972-1982.'
American Journal of Sociology 111:1871-1909.
doi:10.1086/499908
.
This function calculates ideological distance scores based on the calculation created by Grossback et al. (2004) and clarified by Cruz-Aceves and Mallinson (2019). This calculation is based on state ideology data (by year) provided by Richard C. Fording (https://rcfording.com/state-ideology-data/) and used in Berry et al. (1998). This function can be applied to any unit of analysis and time level for any type of policy adoption.