Post Tests on a one-group pre-test/post-test research design

[10girl]

I have conducted a survey as a pre-test. Is it okay for the post-test to be a semi-opened questionnaire regarding the same content. Will validity be an issue?

 

[trinker]

I have conducted a survey as a pre-test. Is it okay for the post-test to be a semi-opened questionnaire regarding the same content. Will validity be an issue?

I would say yes considering both measures are researcher made. How do you know they're measuring the same thing?