how to calculate the sensitivity and spentifity about metagenomic gene prediction

Question

[jinxyhucy521]

I am doing some research about metagenomic gene prediction.The method is ab initio gene prediction

method.I have predicted the labels of the positive and negative open readind frames(ORFs)

respectively,and I am not sure how to calculate the sensitivity and spentifity,I thing I can't

calculate the sensitivity and spentifity based the ORFs,because we can get several ORFs from the

fragment.And some ORFs from the same fragment have been overlapped.

So I hope that I can get help from the people who are doing this aspect research----metagenomic gene

prediction. Thank you very much!!