The next step in projecting the growth of the band program is to study growth projections of the district. If you have access to a demographic study report, this will give you fairly accurate information in regards to district growth predictions.
If you do not have a demographers report, it helps to use district logs of enrollment over the past five years or so. You can look for trends in growth over that period of time to get a percentage of growth to then apply to your district growth projections in your 5 Year Plan.
It is important to look at all campuses when coming up with your numbers. You will have access to actual numbers for any given year, and especially the current year in grades K-12 which can be a good indicator of your band numbers even without growth.
Using data percentages from middle school and high school enrollment AND district growth projections, you can accurately project future band enrollment and predict growth over a period of at least five years.