A very good question … the index is calculated as your number (sales, visitation, purchase conversion, etc) divided by the community average number. Therefore, 100% is “average” and less than 100% is below average.
The key is to watch how the index moves over time e.g. how does your current month index compare to your YTD etc. This tells you if you are growing slower or faster than your peers. Choose index only on the graph for a month to month view of your index and you can see your relative trend very easily.
In this example, we are looking at the Wine Sales index of a Napa winery. We can clearly see an upward trend in their index. This shows that even though they are below the total average, they are growing their Wine Sales faster than the average Napa winery.