# Short term for Probability of Type I error

When comparing statistical tests, one often compares

1. the probability of committing a Type 1 error, and
2. the probability of not committing a Type 2 error.

While (2) can be concisely termed 'power', is there a concise term for the (1)?

(I don't think significance is the right term)

• – whuber Dec 31 '14 at 0:10
• The radar literature calls the two probabilities as the "false-alarm probability" and "false-dismissal probability" which terms I find easier to remember than the bland and unimaginative "Probability of Type 1 error" and "Probability of Type 2 error". – Dilip Sarwate Dec 31 '14 at 0:16
• @whuber, I suppose by that link you are suggesting 'false positive rate'? But just like I prefer 'power' over 'sensitivity' because it sounds more generic (or discipline-independent), I still wonder if there is an equivalent term for (1). But thanks for the link anyway. – qoheleth Dec 31 '14 at 1:21
• Specificity is the only one-word term I can think of. I don't find it memorable, so I just say "$1-\alpha$". Nobody gets confused about what that means. – Glen_b -Reinstate Monica Dec 31 '14 at 2:03
• A nominal size. – Khashaa Dec 31 '14 at 6:04

1. Significance level $\alpha$, see here
2. Power $1-\beta$, sensitivity or recall rate
• as mentioned in my original question, I don't think 'significance' is the right term. Yes, $\alpha$ certainly coincides with the numerical value of (1), but I think it is describing the other side of the same coin. After all, there is nothing significant about rejecting a correct null hypothesis. – qoheleth Jan 5 '15 at 7:00