How might data be collected for this target response?The BCBA could check data being done after each session.
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.

The BCBA could check data is done after each session and staff are incentivized for completing data. Also the BCBA should look at reducing the response effort for the data if the data is too cumbersome for the staff.