Trend analysis involves the collection of information from multiple time periods and plotting the information on a horizontal line for further review. The intent of this analysis is to spot actionable patterns in the presented information. In business, trend analysis is typically used in two ways, which are as follows:
Revenue and cost analysis. Revenue and cost information from a company's income statement can be arranged on a trend line for multiple reporting periods and examined for trends and inconsistencies. For example, a sudden spike in expense in one period followed by a sharp decline in the next period can indicate that an expense was booked twice in the first month. Thus, trend analysis is quite useful for examining preliminary financial statements for inaccuracies, to see if adjustments should be made before the statements are released for general use.
Investment analysis. An investor can create a trend line of historical share prices, and use this information to predict future changes in the price of a stock. The trend line can be associated with other information for which a cause-and-effect relationship may exist, to see if the causal relationship can be used as a predictor of future stock prices. Trend analysis can also be used for the entire stock market, to detect signs of a impending change from a bull to a bear market, or the reverse.
When used internally (the revenue and cost analysis function), trend analysis is one of the most useful management tools available. The following are examples of this type of usage:
Examine revenue patterns to see if sales are declining for certain products, customers, or sales regions.
Examine expense report claims for evidence of fraudulent claims.
Examine expense line items to see if there are any unusual expenditures in a reporting period that require additional investigation.
Extend revenue and expense line items into the future for budgeting purposes, to estimate future results.
When trend analysis is being used to predict the future, keep in mind that the factors formerly impacting a data point may no longer be doing so to the same extent. This means that an extrapolation of a historical time series will not necessarily yield a valid prediction of the future. Thus, a considerable amount of additional research should accompany trend analysis when using it to make predictions.