How might data be collected for this target response?Supervisor uses a checklist to record the occurrence / non-occurrence of essential work responsibilities.
Identify several interventions that might help improve response rates. Place them in order with the least-restrictive at the top so that the interventions may be introduced systematically, adding more restrictive / less favorable interventions after the outcomes of less restrictive options have been measured.

Staff "caught being good" style raffle.
"Employee of the week" style recognition board.
Observation and feedback from supervisor.
Write ups and escalating consequences (e.g. probation) for non-compliance with essential job functions.