Height

Height is one of the correlates that measured size studies have looked at, alongside weight, foot size and other body measurements, and it is worth taking seriously as a genuine research question rather than dismissing it just because folk versions of the claim are everywhere. What the data actually support is narrower than the folk version by a wide margin.

A weak positive correlation, in large samples

Where studies have tested for a relationship between height and length, the reported finding is a weak positive correlation - taller men are, on average and across a large enough sample, very slightly more likely to measure longer. Veale et al. (2015) examined correlates of length within its pooled data as part of assessing what the dataset could and could not support, and a relationship of this kind, where one exists, sits at the weak end of what gets called a correlation in this literature - present, statistically real given a large enough sample to detect it, and small in practical size. This site will not state a coefficient without a specific verified figure to attach it to; the defensible claim is direction and rough strength, not a precise number to quote elsewhere.

Why "real" and "useless for prediction" are both true at once

This is the part that trips people up about weak correlations generally, not just this one. A correlation can be statistically real - meaning it is very unlikely to be a fluke of the particular sample studied - while still being far too weak to use as a predictor for an individual. With a weak correlation, knowing one man's height narrows the plausible range of his length only slightly, and the overlap between "shorter men's" and "taller men's" length distributions is large enough that height tells you almost nothing useful about any one person you might apply it to. A large sample is what makes a weak effect detectable and statistically significant in the first place; it does not make the effect large enough to bet on.

Why the claim persists anyway

The height-length belief circulates as a tidy piece of folk reasoning - taller people are "bigger" generally, so surely everything scales together - and a genuine, if weak, statistical finding gives it just enough cover to survive being tested. People also tend to remember confirming cases and forget disconfirming ones, which is a general feature of how anecdote survives contact with population data, not something specific to this topic.

What this does not license

It does not license using height as a stand-in for a measurement, does not support a specific ratio or formula linking the two, and does not mean any individual case - taller and smaller, shorter and larger - is an exception to a rule, because there was never a strong enough rule for anyone to be an exception to.

Two related folk correlates get their own separate treatment because each has its own specific literature and its own specific caveats: the shoe-size claim, which has been tested directly and found wanting, and the finger-ratio literature, which is a small and different kind of research. Height is worth treating on its own rather than lumped in with either.

None of this is a measurement in the sense this site otherwise covers - correlating two body measurements across a population is a different exercise from taking either measurement carefully, and it is a different exercise again from a subjective judgement. A rating platform is not testing for a height correlation, and a photo submitted to an AI-based estimator, scored by a human judge, or rated alongside a gallery of others typically will not include a height figure at all, so the correlation described here has no bearing on what any of those assessments produce.