twoAxisTo01range.R

# The microsoft report whose number use makesme sad
# New Zealand’s Generative AI opportunity
# https://msftstories.thesourcemediaassets.com/sites/433/2024/08/New-Zealands-Generative-AI-Opportunity.pdf

# impact to date 
# UNDERSTANDING AOTEAROA NEW ZEALAND: THE IPSOS AI MONITOR 2025
# https://www.ipsos.com/sites/default/files/ct/news/documents/2025-08/Ipsos-AI-Monitor-2025%20NZ%20version.pdf

# productivity
# https://infoshare.stats.govt.nz 
# Economic Indicators - Productivity Statistics - PRD
# Table: Productivity Indexes (ANZSIC06) (Annual-Mar)


library(ggplot2)
library(scales)
library(systemfonts)


# Theme, look, and style stuff ----------------------------

dual_ax_L <- "#E69F00"
dual_ax_R <- "#56B4E9"
offwhite_shade <- "#FDFDFDFD"

# These are the font declarations for my Mac w. Lexend Deca added
# Your kind of computer may be different

bodyfont <- "Lexend Deca Thin"
systemfonts::register_variant(name = bodyfont, 
                              family = "Lexend Deca",
                              weight = "ultralight"
)

headfont <- "Lexend Deca Medium"
systemfonts::register_variant(
  name = headfont,
  family = "Lexend Deca",
  weight = "medium"
)

theme_david_splitaxis <- function(){
  theme_minimal(base_family=bodyfont,
                header_family=headfont,
                base_size = 9,
                ink = "#000000", 
                paper = "#FFFFFF", 
                accent = "red") %+replace% 
    theme(text=element_text(family=bodyfont),
          axis.line = element_line(linewidth=0.2),
          axis.line.y.left =  element_blank(),
          axis.line.y.right = element_blank(),
          axis.text.y.left   = element_text(color = dual_ax_L, margin = margin(t = 5, r = 5, b = 5, l = 5, unit = "pt")),
          axis.text.y.right  = element_text(color = dual_ax_R, margin = margin(t = 5, r = 5, b = 5, l = 5, unit = "pt")),
          axis.ticks = element_line(linewidth=0.2),
          axis.ticks.y.left  = element_line(color = dual_ax_L),
          axis.ticks.y.right = element_line(color = dual_ax_R),
          axis.title = element_text(size = 9),
          axis.title.x.bottom = element_text(margin = margin(t = 7, r = 5, b = 0, l = 5, unit = "pt")),
          axis.title.y.left  = element_text(color = dual_ax_L, hjust = .9, margin = margin(t = 5, r = 7, b = 5, l = 7, unit = "pt")),
          axis.title.y.right = element_text(color = dual_ax_R, hjust = .1, margin = margin(t = 5, r = 7, b = 5, l = 7, unit = "pt")),
          panel.background = element_rect(fill = "#FFFFFF", colour = NA, linewidth=NULL),
          panel.grid = element_blank(),
          panel.spacing = unit(1, "lines"),
          plot.background = element_rect(fill = offwhite_shade, colour=offwhite_shade),
          plot.caption = element_text(margin=margin(t = 5, r = 5, b = 5, l = 5, unit = "pt"), lineheight = 1.15, size=8, hjust=1),
          plot.caption.position = "plot",
          plot.margin = margin(t=10,r=10,b=10,l=10),
          plot.subtitle = element_text(lineheight = 1.18, size=10, margin=margin(t = 0, r = 5, b = 20, l = 10, unit = "pt"), hjust=0),
          plot.title = element_text(lineheight = 1.18, size=12, margin=margin(t = 5, r = 5, b = 10, l = 10, unit = "pt"), hjust=0, vjust=0),
          plot.title.position = "plot",
          # strip titles are inside the facets, not that this one is a facet graph
          strip.background = element_blank(),
          strip.clip = "off",
          strip.text = element_text(margin = margin_part(b = -15, l = 6), hjust=0, size = rel(1), colour="#00000099")
    )
}

# Graph data -------------------------------------------

d28 <- data.frame(Yearis = c(2023,2024,2025),
                  Productivity = c(0,-0.6,-1.47),
                  AI.change = c(0,2,6))

# left = AI.change
# right = productivity
left_title = "% change in people\nimpacted by AI since 2023"
right_title = "% change in Total Multifactor\nProductivity since 2023"

# am mapping into an underlying 0 to 1 range
# this code was developed to use part ranges
# so the two sides can display as part ranges
# for a classic double axis graph set both mins to 0 and maxs to 1
# and don't plot the rect annotations

yleftlow = 0.51
ylefthigh = 1
yrightlow = 0
yrighthigh = 0.49

# ranges before
left_orginal_range   <- range(d28$AI.change, na.rm = TRUE)
right_orginal_range <- range(d28$Productivity, na.rm = TRUE)

# scaled variables in their respective new ranges
# Create scaled variables in [0,1] space
d28$left_scale <- rescale(d28$AI, to = c(yleftlow, ylefthigh), from = left_orginal_range)
d28$right_scale <- rescale(d28$Productivity, to = c(yrightlow, yrighthigh), from = right_orginal_range)

# labels will need converting back to original values, so make inverse functions

# Inverse transform for left axis
inv_left <- function(y) {
  rescale(y, from = c(yleftlow, ylefthigh), to = left_orginal_range)
}

# Inverse transform for right axis
inv_right <- function(y) {
  rescale(y, from = c(yrightlow, yrighthigh), to = right_orginal_range)
}

# Make the graph -----------------------------------------------

ggplot(d28, aes(x = Yearis)) +
  # A bit of shading might be nice if the areas are not the same
  annotate("rect", xmin = -Inf, xmax = Inf, ymin=yleftlow, ymax=ylefthigh,
           fill = dual_ax_L, alpha=.05) +
  annotate("rect", xmin = -Inf, xmax = Inf, ymin=yrightlow, ymax=yrighthigh,
           fill = dual_ax_R, alpha=.05) +
  #but all the rest applies even if both axes are 0 to 1
  geom_line(aes(y = left_scale), colour = dual_ax_L, linewidth = 0.5) +
  geom_line(aes(y = right_scale), colour = dual_ax_R, linewidth = 0.5) +
  annotate("segment", x = -Inf, xend = -Inf, 
           y = yleftlow, yend = ylefthigh,
    colour = dual_ax_L, linewidth = 0.5) +
  annotate("segment", x = Inf, xend = Inf, 
           y = yrightlow, yend = yrighthigh,
           colour = dual_ax_R, linewidth = 0.5) +
  theme_david_splitaxis()+
  # left = AI.change
  scale_y_continuous(
    limits = c(0, 1),
    
    breaks = seq(yleftlow, ylefthigh, length.out=3),
    labels = function(y) round(inv_left(y), 2),
    name = left_title,
    
    sec.axis = sec_axis(
      ~ .,
      breaks = seq(yrightlow, yrighthigh, length.out=3),
      labels = function(y) round(inv_right(y), 2),
      name = right_title
    )
  ) +
  scale_x_continuous(breaks=2023:2025) +
  labs(
    x = NULL,
    title = "Last week Microsoft cited up to 102 billion added to NZ GDP by 2038
through increasing AI use increasing national productivity.",
    subtitle = "As that model began in 2023, it has gone along for long enough to actually check
the relationship between how AI and productivity changed since 2023",
    caption = "Source: IPSOS AI MONITOR 2025 people who AI has changed their life
Productivity: Stats NZ Infoshare - Economic Indicators - Productivity Statistics
Made by David Hood, 2026-04-28")

ggsave(
  filename = "ggskyd28v2.jpg",
  width = 2016,
  height = 1134,
  units = "px"
)