Aging data: The purpose of Updating/Aging the Data is to account for inflation. The percentage you use is up to you depending on your time line (the age of the survey data plus how long you think it will take to implement the new plan). Basically, the survey is a snapshot of wages at the time of the survey. We know from the casebook that the survey data is already six months old, which means that wages have increased by some amount since then. It is also reasonable to expect that it will take some amount of time before the new system is implemented which means the survey data will be even older. For example, if you think that it will take six months to implement, then the data that you will be basing your pay ranges on will be a year old. To account for the time lag between data collection and implementation is to adjust (i.e., age) the survey data by some percent (i.e., the inflation rate)