Which Ancestries Does 23andMe Botch Most Badly?

There is a somewhat widely known problem with the 23andMe ancestry estimation techniques for Koreans. It turns out, that the company's own data confirms this fact. 

The Company has a chart measuring precision and recall for each ethnic category. Precision is the likelihood that a particular genetic unit estimated to be from someone of a particular ethnicity really is from a person of that ethnicity. Recall is the likelihood that a gene from a person of a particular ethnicity is accurately classified as such. Here is the breakdown (with poor performance noted in bold):

POPULATION	PRECISION (%)	RECALL (%)
Sub-Saharan African	99	99
West African	97	96
East African	95	89
Central & South African	100	89
East Asian & Native American	99	99
Native American	99	86
East Asian	97	97
Japanese	98	92
Korean	86	62
Yakut	96	78
Mongolian	89	53
Chinese	93	91
Southeast Asian	95	70
European	99	99
Northern European	95	85
British & Irish	90	39
Finnish	95	86
French & German	78	8
Scandinavian	86	34
Southern European	93	66
Balkan	88	42
Iberian	92	51
Italian	88	50
Sardinian	96	62
Eastern European	90	50
Ashkenazi Jewish	97	93
Middle Eastern & North African	95	83
Middle Eastern	90	76
North African	95	77
South Asian	99	95
Oceanian	100	95

Koreans are known to be often misclassified and sure enough, the numbers are bad. Only French and German rates lower than Korean by predictive accuracy. There are less accurate recall rates than those for Koreans, but 62% is nothing to write home about and it is far less accurate than for other East Asian ancestries.

There are also known problems with Southern and Eastern Europeans, all of whom have very low recall rates. Among Northern Europeans, only Finnish people really stand out as distinct.