Is data really necessary? Can't you just describe the behavior you think is lacking, why you think that behavior is important, and then ask them what they think

Is data really necessary? Can't you just describe the behavior you think is lacking, why you think that behavior is important, and then ask them what they think? If you can't come to consensus with your employee about what aspects of their job matter, then you have a bigger problem than poor performance. I don't think having data or metrics is really critical here. Some people like to think in metrics and that's great if you like it, but I don't think that's universal, necessary, or sufficient for a relationship that facilitates good performance.