Editing 2892: Banana Prices

{{comic
| number    = 2892
| date      = February 9, 2024
| title     = Banana Prices
| image     = banana_prices_2x.png
| imagesize = 564x378px
| noexpand  = true
| titletext = It's a linear extrapolation, Michael. How big could the error be? 10%?
}}

==Explanation==
{{incomplete|Created by a MANDALORIAN BANANA GRABBER - Please change this comment when editing this page.}}

[https://www.youtube.com/watch?v=Nl_Qyk9DSUw ‘It’s one banana, Michael. What could it cost, $10?'] is a line from an {{w|Arrested Development}} episode (Season 1, Episode 6, "Charity Drive", 2003) that became a well-known meme used to mock out-of-touch elites. The character who spoke this line (Lucille Bluth, a wealthy socialite) made a satirically high estimate for the price of a banana because she had never bought her own groceries. The implication is that she sees $10 as a trivially small amount of money, and has trouble conceiving of anything that costs less.  According to the graph, the banana price at the time of that episode was actually just under 25 cents, and the price at the time of this comic’s publication (2024) is around 30 cents.

However, the premise of the bananas Lucille was talking about were frozen and chocolate-dipped treats. Still, the average price for that type of banana would range between $1.25 and $3.50 in the early 2000s (depending on location, and whether it was served with additional toppings), which may be equivalent to $2.50 - $5.00 by 2023. By using the current highest value and the {{w|Rule of 72}}, this indicates that a general inflation rate of no more than 0.72% would give us the century of leeway, or 1.44% from the lower end (still well below the given historical rate that demonstrably applies across the past twenty years).

The comic is a wry observation that the irony of this sitcom line will "probably" be anachronistically meaningless in a century or so, presenting three predictions of banana prices over the next 250 years that each extrapolate from the current 2024 price using different long-term inflation rates. 

The three extrapolations use (1) the general inflation rate (a value dominated by the cost of housing), (2) the inflation rate for fresh fruit, and (3) 45 years of historic banana prices. Those models present the joke becoming reality around 2140, 2170 and 2250, respectively.

The caption’s claim that banana prices could exceed $10 in a century are based on the fastest rising extrapolation, the one for “general inflation.” This extrapolation predicts a banana’s price to rise from 30 cents to $10 in approximately 115 years. This 115-year increase corresponds to an average long-term inflation rate of about 3.2%, close to the historic US average.

The reference to "BLS/St. Louis FRED" refers to The {{w|Bureau of Labor Statistics}} and {{w|St. Louis Fed Financial Stress Index|St Louis FRED}}, widely respected sources of economic data. The Federal Reserve Bank of St. Louis maintains the FRED database; FRED stands for Federal Reserve Economic Data.

The title text continues the ignorant tone of Lucille Bluth to make two jokes.
# A satirical guess of 10% error. The humor is that the three predictions themselves (from 115 years to 220 years) predict wildly different years of a $10 banana. Economic extrapolation into the distant future is at most an educated guess, with an expected error far in excess of 10%. Guessing such small errors in such speculative projections is just as clueless as guessing that individual bananas cost so much. 
# An ignorant reference to these as “linear extrapolations.” While they look linear, they are actually ''exponential'' extrapolations. The graph is log-linear, with price as a logarithmic scale on the vertical (left) axis, which makes it possible to visualize the exponential growth extrapolation as a straight line. In other words, an extrapolation line on a graph with a logarithmic scale is actually exponential. 

It’s not typical to plot commodity prices on a log-scale, but maybe Randall did this to allow himself to make this subtle “linear extrapolation” joke.

This comic uses several common xkcd themes:
* '''Log scales''' and their peculiarities are a recurring xkcd theme, and this is the second comic in a row to play with logarithms (the prior one being [[2891: Log Cabin]]). 
* It's also the second comic in the last four to involve '''predictions across centuries''' (i.e. [[2889: Greenhouse Effect]]). 
* Another '''extrapolation''' comic includes [[605: Extrapolating]]. And this comic looks a lot like [[1007: Sustainable]].

===Discussion of price references in fiction===
It's common for fictional works to avoid mentioning actual prices or amounts of money. One reason is that presenting an actual amount risks the work becoming dated by inflation. A price that's presented as surprisingly high can lose its impact as the value of money changes, making it difficult for a punchline or a dramatic moment to land. In this case, however, the number is so exaggerated (being around 40 times higher than the actual price of a banana), that it's unlikely for inflation to impact the joke in the immediate future. Twenty years after the episode first aired, the joke works just as well as it did. 

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A graph with the x-axis showing time, from the years 1950 to around 2275. The y-axis is a log scale showing the price of a banana from $0.10 to over $10.00. A label called "Price of a banana (BLS/St. Louis ''Fred''[https://fred.stlouisfed.org/])" show a rising trend in the price of a banana. There are two dots on that trend. One is labeled "Episode airs" and the other one "Now". 3 extrapolations shown as dashed lines labeled "General inflation rate", "Fresh fruit price trend" and "Banana price trend" extend until reaching the $10 mark, indicated by 3 dots.]

:[Caption above the graph:] "It's one banana, Michael. What could it cost? $10?"

:[Caption below the panel:] That line probably has another century or so left.

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Timelines]]
[[Category:Fiction]]
[[Category:Extrapolation]]
[[Category:Food]]