Chloe

Appropriate levels of standyby/on-call and callout payments will vary immensely with the frequency with which people are actually called (from rarely to every time) and the  frequency/duration with which they actually have to attend the workplace to resolve a problem - a IT operations specialist who can solve a problem by remote connection dosn't face the same constraints as a person who has to physically go the the workplace to repair part of a production chain so that 24-hour production can resume.

My advice would be to review the actual calls and call-outs over the last 2-3 years to see if there are any trends that arise. When reviewing, review not only calls/call-outs but also the level of payments made under your 3 sytems. This will give you an excellent starting point.

There is cleary a balance to strike between the two componenents, and I would be inclined to favour the call-out element in situations where people are rarely called out. On the other hand, if someone is on call for 2 weeks and is regularly called (but does not attend) 2 or three times during each 2-week period, then a more generous standy allowance would be more appropriate.

Don't forget also that the user departments should review these costs every 6 months to monitor for patterns (mean breakdown frequency for instance) in order to contain what are their costs (not your costs).