targets <- data.frame(category1 = rep(c('1', '2', '3', '4', '5'), 2), category2 = rep(c('a', 'b'), 5), value = abs(rnorm(10)))
outcomes <- data.frame(category1 = rep(c('1', '2', '3', '4', '5'), 2), category2 = rep(c('a', 'b'), 5), value = targets$value + rnorm(10, sd = 0.1))

library(ggplot2)

ggplot() +
  geom_bar(data = outcomes, mapping = aes(x = category1, y = value, fill = category2), stat='identity', position = 'dodge', alpha = 0.5) +
  geom_point(data = targets, mapping = aes(x = category1, y = value, color = category2), position = position_dodge(width = .9), size = 5) +
  labs(fill = 'Model Estimated Values', color = 'Data Targets') +
  theme_bw()