topic Re: Logistic regression - how is percent concordant calculated? in New SAS User

Logistic regression - how is percent concordant calculated?

adrfinance — Thu, 06 Feb 2020 16:01:59 GMT

The output of a logistic regression gives me the following information:

Association of Predicted Probabilities and Observed Responses
Percent Concordant	71,3	Somers' D	0,457
Percent Discordant	25,6	Gamma	0,471
Percent Tied	3,1	Tau-a	0,164
Pairs	56483682	c	0,728

and

Response Profile
OrderedValue	deterioration	TotalFrequency	TotalWeight
1	0	13542	19214,7
2	1	4171	7150,3

What is the formula to calculate the percent concordant from the above?

Re: Logistic regression - how is percent concordant calculated?

PaigeMiller — Thu, 06 Feb 2020 16:03:57 GMT

Many many articles on the internet explaining percent concordance.

Re: Logistic regression - how is percent concordant calculated?

adrfinance — Thu, 06 Feb 2020 16:06:02 GMT

So is there a way to calculate it using the information above?

Re: Logistic regression - how is percent concordant calculated?

ballardw — Thu, 06 Feb 2020 16:41:50 GMT

@adrfinance wrote:

So is there a way to calculate it using the information above?

It looks like the percent concordant was already calculated as posted in the first post.

So I think you may be missing a detail or two at this question.

Re: Logistic regression - how is percent concordant calculated?

Reeza — Thu, 06 Feb 2020 18:31:16 GMT

Here is some annotated output from PROC LOGISTIC that will help you interpret the table. You may need the output predicted and actual values table to recreate the calculations.

https://stats.idre.ucla.edu/sas/output/proc-logistic/

@adrfinance wrote:

The output of a logistic regression gives me the following information:

Association of Predicted Probabilities and Observed Responses

Percent Concordant 71,3 Somers' D 0,457

Percent Discordant 25,6 Gamma 0,471

Percent Tied 3,1 Tau-a 0,164

Pairs 56483682 c 0,728

and

Response Profile

OrderedValue deterioration TotalFrequency TotalWeight

1 0 13542 19214,7

2 1 4171
7150,3

What is the formula to calculate the percent concordant from the above?

Re: Logistic regression - how is percent concordant calculated?

adrfinance — Fri, 07 Feb 2020 07:27:46 GMT

Sorry, I don't understand what you are saying. How is it calculated?