Before revision:  Through analysis of the trade-off between giving incentives to agents and saving the cost of data processing and analysis , we obtain characterizations of optimal monitoring technologies such as information aggregation, strict MLRP, likelihood ratio-convex performance classification, group evaluation in response to high monitoring costs, and assessing the various task performances according to agents' endogenous tendencies to shirk.
After revision:  Through analysis of the trade-off between giving incentives to agents and saving the monitoring cost , we obtain characterizations of optimal monitoring technologies such as information aggregation, strict MLRP, likelihood ratio-convex performance classification, group evaluation in response to high monitoring costs, and assessing the various task performances according to agents' endogenous tendencies to shirk.