The article looks at how software companies estimate their projects and why they choose certain methods. They did a survey with senior managers from 18 companies and project managers from 52 projects. The results show that on average, projects exceed their estimated effort by 41%. The accuracy of estimation hasn't improved much in the past 10-20 years. Expert estimation is the most common method used. Formal estimation models don't seem to make a big difference in accuracy. Software managers often think their estimation accuracy is better than it actually is.