People do what we ‘inspect’ not what we ‘expect’ and so regular ‘on track’ reviews are essential to make sure expectations are being met. As part of the setting expectations conversation you should agree how and when progress will be measured. Consider brief monthly ‘on track’ reviews or schedule brief verbal or email reports. Make sure though that the employee fully understands your ‘no surprises’ policy, meaning they should talk to you as soon as it becomes apparent they may not be able to deliver the agreed expectations.