Many people in the repair industry still believe that the repair tech knows both the How and What of a repair. This belief should have ended around 2010, but discouragingly it is still prevalent in the industry in 2020.
In facilities that still hold to this outdated model the technician is assigned a repair and given only the estimate as information. In most cases that information was only whether to repair or replace a part and the time that was allotted to the task. Based on prior experience he would be expected to know what to do. If he had repaired a bent frame rail many times in the past, then the bent frame rail he was dealing with now could be repaired using that knowledge. Until around 2010, with most cars using the same frame material and manufacturing techniques this prior knowledge was usually sufficient.
Now, a vehicle structure can be made of many different types of steel and other materials, each of which have a specific design purpose and specific techniques for repair or replacement. All of this metal looks very similar and if the tech is not given full information about the materials used in the damaged area, he will not be able to repair the car to Next Accident Ready condition.
This is no criticism of a conscientious and qualified repair technician. There is a tremendous amount of skill and knowledge in How to do a repair but What to do can only come from information provided by others. The Pre-Estimate Vehicle researcher can verify the material used and the Estimator can use that information as part of his repair report. It is this repair report that the technician uses as the What information needed for the correct repair.
An analogy is the relationship between the surgeon and the support team he works with. The highly trained surgeon cannot do much with a sedated patient on the operating table if he is not given specific information. He has the highly skilled How, but he needs the What information from the support team to properly use apply that highly skilled How.
The following post, with photos of a cutaway 2016 Honda Civic model, provides an example of how the How and What come together for successful repair.