Field note · April 7, 2024
The category that eats the chart
6 values with 24.2% concentrated in one of them, and what that does to every chart downstream.
category on retail-orders has 6 values, and one of them is 24.2% of the data.
apparel— 1,696 rows, 24.2%home— 1,279 rows, 18.3%grocery— 1,188 rows, 17.0%beauty— 1,088 rows, 15.5%electronics— 960 rows, 13.7%
The top three take 59.5% between them. With only 6 values there is no tail to worry about, which makes this a genuinely easy column to chart.
select category,
count(*) as rows,
round(100.0 * count(*) / sum(count(*)) over (), 1) as pct,
round(avg(unit_price_usd)::numeric, 2) as avg_unit_price_usd
from retail_orders
group by 1
order by rows desc;The second column is the one that matters. Share of rows tells you what is common; avg_unit_price_usd tells you whether the common thing is the important thing. They disagree more often than not, and a chart that shows only the first is answering the easier question.
Decide what happens to the tail before you plot it. "Other" as an explicit bucket is honest; twelve slivers is not, and neither is silently taking the top eight.