What are some ways we could tie federal legislative pay to performance?

Executive pay legislation has attempted, and often failed, to balance executive conflicts of interests by tying their pay to certain performance metrics of the corporations they lead.

The main drawback of big government, however, is that pay is guaranteed, regardless of performance. And connections, regardless of performance, increase the perceived value of exiting legislators when re-entering the private industry. So, there is a perverse incentive against risk, innovation, etc., and towards mediocrity and “consensus maintenance.”

In what ways can we attempt, barring Constitutional restrictions at this time, to attempt to tie legislative pay to performance? What metrics should be used to judge this? And what unintended consequences would need to be controlled for?