How would an analyst take inflation into account in interpreting ratios?
Inflation tends to increase income statement amounts year-by-year. New plant and equipment enters the books at ever higher prices each year while existing fixed assets do not reflect the price changes, continuing to be recorded at their historical costs (less depreciation). The result is a systematic change to the numbers used to calculate ratios and the potential for distortions in time-series and cross-sectional comparisons. While many financial analysts ignore the issue, assuming that the effect of inflation is the same on all companies, sophisticated analysts attempt to separate changes caused by inflation from changes due to an underlying strengthening or weakening of the company itself.