I would recommend the following for your consideration:
Identify the roles which have the lowest turn-out ratio. Focus on the reason why talent deal it that way. Ideally, generic competencies have greater market for job seekers. Whereas niche skill sets have focused offerings. Pre-wire the recruitment process accordingly.
In case of mass hiring you may have little control. However, when hiring numbers are deffer over a period of time, align your hiring team closely with the shortlist and probable candidates. Add the ones who have been made an offer on the social networking sites, LinkedIn necessarily and other social recruitment sites. This restricts their scope to misbehave.
Above all maintain transparency about the offer made. Often, the candidates fail to understand the offer and realize it too late. Make sure they have a clear view to the 'take-home' and future growth, if any.
Look for commitment towards the role in the candidate. Too often, talents fake this expression to impress the recruiters. Ask for high engagement activities during the hiring process. A project manager used to make the candidates work on a failed project, for a day as a part of the skill identification. Here, he used to primarily gauge the attitude of the candidate to push through.