This may be the one who seems to have the more stable employment outlook or higher salary, which can be an indicator of his or her ability or pay rent on time.
If previous research did not include contacting prior landlords, that may be a good choice. Some habits and factors may not show up in documentation. For example, a particularly good tenant might have taken exceptional care to ensure her previous home’s condition, which could easily go unrecorded.
Alternatively, one tenant may be able to move in sooner, meaning that the rental spends less time vacant. All other factors being equal, that may be a deciding detail.
When making a choice, it is important to ensure that no violations of fair housing law occur. It may be wise to develop an official written policy for choosing between good prospects, not just a set of minimum qualifications. That way, decisions can be consistent over the years and discrimination can be avoided.