How to Check the Contractor Stability

Hi,

I was asked to make a shortlist of Pre-qualified Contractors to limit our tender invitees list, so I was aked also to set a carteria of selection for those pre-qualified contractors.

I set so items including the machinary, number of labour, expected jobs, jobs in hand..etc.

Please, if you have any other suggestions, I will appreciate your help, also, I wish to ask about, How to check Contractors financial stability.

Thanks