Dear Stata listers,

I ran a logistic regression model which has a factor variable Education level (1-No education 2-Primary 3-Secondary 4-Tertiary) against dependent variable Adherence to PrEP (1-Good, 0-Poor). Stata automatically takes first category as reference (...in this case "1-No education").
My supervisor then asked me "Which criteria did you use to choose "1-No education" as your reference category"


Is there a certain criteria of choosing a reference category for factor variables in Logistic regression?

Thank you
Abraham