Harold van Heeringen discusses software estimation and performance measurement. He notes that most software projects have low estimation maturity and experience cost and schedule overruns. Functional size measurement and historical project data can be used to create more objective, repeatable estimates. Estimates should include scenarios for different durations, team sizes, and non-functional requirements. Performance measurement involves collecting project data and comparing actual metrics like productivity and defects to estimates. Benchmarking against industry data provides opportunities for improvement. Accurate estimation and performance measurement processes help create defendable estimates and manage projects based on actual performance.