There are a number of reasons why people aren’t keen on PDR. It may be that reviewees don’t feel comfortable with the idea of their work being “measured” in some way. Perhaps their previous experience of a review process has been difficult. Or perhaps they can’t see the point because their work doesn’t change much and they can’t see how objectives can be set.
Reviewees may not be comfortable with the idea of the work being measured: it is still a reasonable action and good practice for you to discuss expectations in the role, offer feedback and support people to achieve. Institutions that give their staff an opportunity to talk about their work, offer and hear feedback, set realistic objectives and discuss their development are likely to be more effective workplaces. (Engaging for Success, David MacLeod and Nita Clarke, Department for Business, Innovation and Skills, 2011)
If the reluctance is to hear a message about something being done differently, look at our Giving feedback (PDF) guide on how to structure a request for change. Staff who have had a previous difficult experience of a PDR type process will learn to trust the process if they can see that you are being transparent and constructive, so you may need to pay particular attention to the way you conduct the meeting (see our Preparing for the PDR - reviewer (PDF) skills guide).
Reviewees who think that objectives are pointless because they do the same thing every day could agree "maintenance" type objectives with you. A maintenance objective celebrates the fact that staff perform repetitive tasks to a high standard in a way that keeps the department functioning. A example might be: "We need you to continue to do xx by yy in order to keep the lab running effectively."
And at the very least, PDR gives your group members the chance to talk about themselves, how they feel about the job, any factors that affect their work and to hear you say thank you.