I experienced this issue when I was in the public service: It's always difficult to set ambitious targets ourselves. People tend to go towards targets or indicators that already exist, that are familiar to them. Rather than measuring results, people tend to measure the mechanisms used, that is to say what's been produced, how much has been spent or the number of social workers affected, rather than the outcomes they want to achieve, such as the number of healthy people or how many children are thriving in their families.
It's true that the targets set are strange. To remedy that, I believe targets must be set based on departmental objectives. I think ministers need an opportunity to be more involved in setting their targets. House committees like yours could also suggest appropriate targets or performance indicators to departments and agencies.