Are indexes seasonally adjusted?
No. This is an important point for users of the indexes to keep in mind. Wages, the most important component, usually affect the indexes once or twice a year. Cement prices tend to be more active in the spring while fabricated structural steel pricing tends to have monthly adjustments. Lumber prices, more dependent on local pricing and production conditions, are the most volatile and can change appreciably from month to month. Declines in indexes are most often the result of falling lumber prices. The study of an index movement for a period of less than 12 months can sometimes miss these important developments. Users of an index for individual cities should also watch the timing of wage settlements. Stalled labor negotiations may keep the old wage rate in effect longer than a 12-month period, giving the appearance of a low inflation rate.
