Plotting marginal effects fails

[mronkko]

Please specify whether your issue is about:

• [ x] a possible bug
• [ ] a question about package functionality
• [ ] a suggested code or documentation change, improvement to the code, or feature request

The problem seems to be that the "at" attribute of the margins object contains a column named index, but there is no corresponding column in the summary(margins) output.

Put your code here:

## load package
library("margins")

## code goes here
library(carData)

data(Prestige)

womenValues <- c(0, 25, 50, 75, 97.51)

m5 <- lm(income ~ education*women, data = Prestige)

mar5 <- margins(m5, variables = "education",
                at = list(women = womenValues))

plot(mar5)

10: stop("undefined columns selected")
9: `[.data.frame`(summ, , names(attributes(x)[["at"]]), drop = FALSE)
8: summ[, names(attributes(x)[["at"]]), drop = FALSE]
7: unique(summ[, names(attributes(x)[["at"]]), drop = FALSE])
6: plot.margins(mar5)
5: plot(mar5) at .active-rstudio-document#13
4: eval(ei, envir)
3: eval(ei, envir)
2: withVisible(eval(ei, envir))
1: source("~/.active-rstudio-document", echo = TRUE)

## session info for your system
sessionInfo()

R version 4.0.0 (2020-04-24) Platform: x86_64-apple-darwin17.0 (64-bit) Running under: macOS Catalina 10.15.4

Matrix products: default BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib LAPACK: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRlapack.dylib

locale: [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages: [1] stats graphics grDevices utils datasets methods base

other attached packages: [1] carData_3.0-4 margins_0.3.23 maxLik_1.3-8 miscTools_0.6-26

loaded via a namespace (and not attached): [1] Rcpp_1.0.4.6 pillar_1.4.4 compiler_4.0.0 tools_4.0.0 digest_0.6.25 lifecycle_0.2.0 tibble_3.0.1
[8] gtable_0.3.0 lattice_0.20-41 pkgconfig_2.0.3 rlang_0.4.6 Matrix_1.2-18 cli_2.0.2 rstudioapi_0.11
[15] dplyr_0.8.5 vctrs_0.3.0 grid_4.0.0 tidyselect_1.1.0 glue_1.4.1 data.table_1.12.8 R6_2.4.1
[22] fansi_0.4.1 prediction_0.3.14 ggplot2_3.3.0 purrr_0.3.4 magrittr_1.5 scales_1.1.1 ellipsis_0.3.1
[29] MASS_7.3-51.6 assertthat_0.2.1 colorspace_1.4-1 sandwich_2.5-1 munsell_0.5.0 crayon_1.3.4 zoo_1.8-8

[vincentarelbundock]

Are you sure you shouldn't be using the cplot command instead? It looks like you care about variation in the marginal effect of education for different values of women, which is exactly what cplot is for.

[duckmayr]

@vincentarelbundock It's probably safe to close this issue... I had the exact same issue as the original poster, and investigating the problem led me to this issue page, and you were 100% right, the problem was just needing to use cplot() rather than plot.margins()

[vincentarelbundock]

@duckmayr thanks, but I didn't open this issue and I don't manage the repository, so I can't close the issue. Maybe the confusion from the fact that I maintain a package with a very similar name ;)