Chapter 33 Inequality: Net Worth by Age Group

LEARNING NOTES

座標軸從數值到增加值

這個教學案例來自紐約時報的「What’s going on in this gragh」系列資料視覺化教學之Teach About Inequality With These 28 New York Times Graphs - The New York Times (nytimes.com) 。該圖表呈現在不同年代、不同年齡層的人所擁有的淨資產（包含土地、存款、投資等減去債務）。該圖表的結果指出，在不同年代的老年人是越來越有錢，但年輕人卻越來越窮（該曲線為減去1989年

淨資產（Net worth）是一個財務術語，指的是一個人或機構的總資產減去總負債後剩餘的價值。換言之，Net worth是一個人或機構在財務上的價值或實力。如果一個人或機構的總資產超過了總負債，那麼其net worth為正值，反之則為負值。在個人財務上，Net worth通常用來評估一個人的財務健康狀況。一個人的Net worth越高，通常代表其擁有更多的財富和投資，並能夠更好地應對突發事件和生活變數。因此，許多投資者和財務顧問都會建議人們注重提高自己的net worth。

Teach About Inequality With These 28 New York Times Graphs - The New York Times (nytimes.com)

Sorted by arrange() function.

p1 <- read_csv("data/interactive_bulletin_charts_agecl_median.csv") %>%
    select(year, Category, Net_Worth) %>%
    group_by(Category) %>%
    arrange(year) %>%
    ungroup()
p1 %>% filter(year <= 1992) %>% knitr::kable()
year Category Net_Worth
1989 Less than 35 16.17019
1989 35-44 112.47530
1989 45-54 195.11630
1989 55-64 195.25554
1989 65-74 154.34277
1989 75 or older 144.29855
1992 Less than 35 16.60780
1992 35-44 79.91050
1992 45-54 139.97745
1992 55-64 203.44104
1992 65-74 176.44667
1992 75 or older 155.35173 
library(gghighlight)
p1 %>% ggplot() + aes(year, Net_Worth, color = Category) + 
    geom_line(linetype="dotted") + 
    geom_point() + 
    gghighlight(Category %in% c("65-74", "35-44")) + 
    theme_minimal() + 
    scale_x_continuous(breaks = NULL) + 
    theme(panel.background = element_rect(fill = "white",
                                colour = "white",
                                size = 0.5, linetype = "solid"))

p2 <- read_csv("data/interactive_bulletin_charts_agecl_median.csv") %>%
    select(year, Category, NW = Net_Worth)  %>%
    group_by(Category) %>%
    arrange(year) %>%
    mutate(increase = (NW-first(NW))/first(NW)) %>%
    ungroup()
p2 %>% filter(year <= 1992) %>% knitr::kable()
year Category NW increase
1989 Less than 35 16.17019 0.0000000
1989 35-44 112.47530 0.0000000
1989 45-54 195.11630 0.0000000
1989 55-64 195.25554 0.0000000
1989 65-74 154.34277 0.0000000
1989 75 or older 144.29855 0.0000000
1992 Less than 35 16.60780 0.0270627
1992 35-44 79.91050 -0.2895285
1992 45-54 139.97745 -0.2825948
1992 55-64 203.44104 0.0419220
1992 65-74 176.44667 0.1432131
1992 75 or older 155.35173 0.0765994 
p2 %>% ggplot() + aes(year, increase, color = Category) + 
    geom_line(linetype="dotted") + 
    geom_point() + 
    gghighlight(Category %in% c("65-74", "35-44")) + 
    theme_minimal() + 
    scale_y_continuous(labels=scales::parse_format()) + 
    scale_x_continuous(breaks = NULL) + 
    theme(panel.background = element_rect(fill = "white",
                                colour = "white",
                                size = 0.5, linetype = "solid"))