pathway: Pathway case

In MMRcaseselection: Case Classification and Selection Based on Regression Results

Description

Calculation of pathway values, defined as the difference between residuals of full model and reduced model lacking the pathway variable. The larger the difference, the more a case qualifies as a pathway case suitable for the analysis of mechanisms.

Usage

pathway(full_model, reduced_model)

Arguments

full_model	Full model including covariate of interest (= pathway variable)
reduced_model	Reduced model excluding covariate of interest

Details

The difference between the absolute residuals of the full and reduced model follows the approach developed by Weller and Barnes (2014): Finding Pathways: Mixed-Method Research for Studying Causal Mechanisms. Cambridge: Cambridge University Press. https://doi.org/10.1017/CBO9781139644501).

The calculation of the absolute difference between the full-model and reduced-model residuals, given a case's reduced-model residual is larger than its full-model residual, follows the proposal by Gerring (2007): Is There a (Viable) Crucial-Case Method? Comparative Political Studies 40 (3): 231-253. https://journals.sagepub.com/doi/10.1177/0010414006290784)

Value

A dataframe with

- all full model variables,

- full model residuals (full_resid),

- reduced model residuals (reduced_resid),

- pathway values following Weller/Barnes (pathway_wb),

- pathway values following Gerring (pathway_gvalue),

- variable showing whether Gerring's criterion for a pathway case is met (pathway_gstatus)

Examples

df_full <- lm(mpg ~ disp + wt, data = mtcars)
df_reduced <- lm(mpg ~ wt, data = mtcars)
pathway(df_full, df_reduced)

MMRcaseselection documentation built on July 1, 2020, 9:55 p.m.