geom_segment - parallel dodging

Question

I am having a 'classical' ggplot problem, very similar to the question discussed here. I tried to solve it like suggested there, but somehow it does not work.

The dataset is:

overall <- structure(list(organization = c("orga_arts", "orga_arts", "orga_arts", 
"orga_arts", "orga_environment", "orga_environment", "orga_environment", 
"orga_environment", "orga_humanrights", "orga_humanrights", "orga_humanrights", 
"orga_humanrights", "orga_labour", "orga_labour", "orga_labour", 
"orga_labour", "orga_neighbor", "orga_neighbor", "orga_neighbor", 
"orga_neighbor", "orga_none", "orga_none", "orga_none", "orga_none", 
"orga_others", "orga_others", "orga_others", "orga_others", "orga_party", 
"orga_party", "orga_party", "orga_party", "orga_patriotic", "orga_patriotic", 
"orga_patriotic", "orga_patriotic", "orga_religious", "orga_religious", 
"orga_religious", "orga_religious", "orga_sports", "orga_sports", 
"orga_sports", "orga_sports", "orga_welfare", "orga_welfare", 
"orga_welfare", "orga_welfare"), among_participants = c(8.5, 
8.5, 8.5, 8.5, 8.7, 8.7, 8.7, 8.7, 2.6, 2.6, 2.6, 2.6, 11.4, 
11.4, 11.4, 11.4, 5.4, 5.4, 5.4, 5.4, 49.9, 49.9, 49.9, 49.9, 
4.9, 4.9, 4.9, 4.9, 5.6, 5.6, 5.6, 5.6, 1, 1, 1, 1, 11.8, 11.8, 
11.8, 11.8, 19.1, 19.1, 19.1, 19.1, 4.4, 4.4, 4.4, 4.4), value = c(10.7, 
10.6, 11.9, 11, 12.9, 10.9, 12.8, 8.8, 4, 5.5, 5.4, 3.2, 12.3, 
10.5, 12, 14.3, 6.9, 7.8, 7.6, 6.5, 46.9, 45.3, 45.1, 47.7, 5.4, 
4.3, 5.4, 5.1, 6.5, 9, 4.5, 5.8, 0.9, 1.2, 1.2, 1.7, 13.2, 12.5, 
12, 10.5, 20.8, 17.3, 19.2, 21.5, 5.7, 5.4, 4.5, 5.4), type = c("issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_corona", "issue_corona_eco", "issue_racism", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_corona_eco", 
"issue_racism", "issue_climate", "issue_corona", "issue_racism", 
"issue_climate", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona", "issue_corona_eco", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona", "issue_climate", 
"issue_racism", "issue_corona_eco", "issue_corona")), row.names = c(NA, 
-48L), class = "data.frame")

I would like to do something like:

ggplot(overall) + 
  geom_segment(aes(x = among_participants, xend = value,
                 y=organization, yend=organization, color=type),
                arrow = arrow(length = unit(0.5, "cm")),
             position=position_dodge(width=space_between_bars))

but obviously with parallel arrows... I know I could do geom_linerange, but then I miss the arrow heads that are important to show the direction of change with the design of the figure I had in mind.

I tried doing something like:

overall$organization_dodged <- ave(as.numeric(overall$organization), overall$organization, 
   FUN = function(x) x + rnorm(length(x), sd = .1))

and then doing the geom_segment with scale_y_continuous per the suggested answer in the question linked above but I could not get it to work.

I also saw in this thread that there was supposed to be an update on this 10 years ago. Maybe that happened, and I am missing an easy fix here that I can't see now?

Answer 1

I bet this can be done more elegantly, but this seems to work:

space_between_bars <- 0.2
overall$type_y_adj = scale(as.numeric(as.factor(overall$type))) * -space_between_bars
overall$y = as.numeric(as.factor(overall$organization)) + overall$type_y_adj

ggplot(overall) + 
  geom_segment(aes(x = among_participants, xend = value, y=y, yend=y, color=type),
               arrow = arrow(length = unit(0.1, "cm"))) +
  scale_y_continuous(breaks = 1:length(unique(overall$organization)),
                     labels = unique(overall$organization), minor_breaks = NULL)