Field note · October 7, 2025

clinical-trial.sex: 2 values, 100.0% in the top three

2 values with 55.3% concentrated in one of them, and what that does to every chart downstream.

1 min read ·Visualization ·visualization practice

Distribution of sex on clinical-trial, because every chart built on it inherits this shape.

  • F — 498 rows, 55.3%
  • M — 402 rows, 44.7%

The top three take 100.0% between them. With only 2 values there is no tail to worry about, which makes this a genuinely easy column to chart.

sql
select sex,
       count(*)                                      as rows,
       round(100.0 * count(*) / sum(count(*)) over (), 1) as pct,
       round(avg(baseline_score)::numeric, 2)             as avg_baseline_score
from clinical_trial
group by 1
order by rows desc;

The second column is the one that matters. Share of rows tells you what is common; avg_baseline_score 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.