She was notable for demonstrating that the correlation between cranial capacity and gender was not a sign of greater intelligence in men compared to women.

It was then an accepted theory in craniology that brain power increased with size, hence skull capacity was a measure of mental ability.

[8] Lee's study drew considerable criticism from her thesis examiners and from eugenicist Francis Galton, who questioned the originality and the scientific quality of her work.

[8] Initially as volunteer,[10] Lee eventually received a salary of £90 a year and worked three days a week.

Her duties included reducing data, computing correlation coefficients, creating histogram bar charts, and calculating new kind of chi-squared distribution statistics.

For her dissertation she had developed a statistical model that estimated the cranial volume of living humans from external skull measurements.

[10] Her research on the statistical analysis of within species variation, a branch of evolutionary biology, continued until 1910 and led her to publish a succession of papers in the Biometrika from 1902 onwards.

Lee's work also contributed to the preparation of tabulated functions, which were frequently used by contemporary statisticians and biologists.

From 1916 to 1918, she also calculated shell trajectories and compiled tables of all kinds for the Anti-Aircraft Experimental Section of the Munitions Inventions Department.

[9] Lee's salary at Bedford College had always been a "women's wage", and the pension scheme had started too late for her to join.

The final blow came in 1909 when Franklin P. Mall applied statistical measures to the study of the frontal lobe and fissures of the human brain, which had been associated with racial and sex differences, in his paper On several anatomical characters of the human brain, said to vary according to race and sex, with especial reference to the weight of the frontal lobe.