Use a survey from a study under review? I developed a survey and my study using the survey is still under review for a publication.  However, my friend wants to use the survey and data for her study. I collected the data only in my school; she wants to collect additional data from a different school.

My concerns are:


If her study is published before mine, my study could be meaningless.
Also, the two studies could be very similar.


Is it okay to allow her to use my survey as well as my data?
I assume that your supervisor already know that you already submitted your work:
If your targeted publication venue allows you to publish pre-print than you may submit your work at arxiv or any other similar public library and give reference to you work in extended work conducted by your supervisor.Otherwise, you can give reference to your work in extended version with status "Under Review".