Using direct method

[Charlie]

Dear QCA expert,

Most of my data is qualitative so I am using the direct assignment method for most of my conditions. I do nevertheless have one condition based on numerical data. I therefore want to use the direct method for this condition.

I have been using the approach laid out by Ragin in his Redesigning Social Inquiry book. However, I got stuck just before being able to set the degree of membership. I am finding this passage impossible to understand: degree of membership = exp(log odds)/[1+exp(log odds)]. I am really unsure about what I need to do with the data I have so far scaled etc. In case it helps I am attaching the table I am using. 

Thanks a lot in advance for your help!

Charlie

[Ingo Rohlfing]

Dear Charlie,

with the formula, you are taking a deep dive into the mechanics of direct calibration. I think this is not necessary for empirical research where you simply want to directly calibrate a variable. At a minimum, you only need to specify the points of full exclusion, the crossover point and the point of full inclusion. Is there a specific reason why you read up on the statistics of direct calibration?

Regards

Ingo

[Adrian Dușa]

On Tuesday, January 27, 2026 at 11:50:23 PM UTC+2:

[...]

with the formula, you are taking a deep dive into the mechanics of direct calibration. I think this is not necessary for empirical research where you simply want to directly calibrate a variable. At a minimum, you only need to specify the points of full exclusion, the crossover point and the point of full inclusion. Is there a specific reason why you read up on the statistics of direct calibration?

Indeed.

For a step by step tutorial on how to use the direct method, please see section 4.2.2 on the Direct method, the “s-shape” functions:

https://dusadrian.github.io/QCAbook/calibration.html#s-shape

And, if you really are interested in understanding the logistic formula, the next section 4.2.3 might help:

https://dusadrian.github.io/QCAbook/calibration.html#logistic

Hope this helps,

Adrian