Index Series

When index numbers are computed for several different periods, all measured against the same base period, the resulting list of values is called an index series. Businesses and economies build index series routinely — tracking company sales, industry-wide sales, or inventory levels (often measured in currency amounts) across successive years. The purpose of such a series is usually to reveal how usage or activity — physical volume, for instance — has grown or shrunk relative to the fixed base, making it possibl …