Input the IRS Schedules C from the 2013–2015 income tax returns into a spreadsheet.

a. Add percent columns to the right of dollar column for each year.

b. Calculate common-sized percentages in the percent columns [divide each number for that year (e.g., 2013) by gross receipts for that year (e.g., 2013)].

c. Review the dollars horizontally across the three years and vertically down each year and identify any material irregularities.

d. Review the percentages horizontally across the three years and vertically down each year and identify any material irregularities.

e. Are there any material trends or material single-year changes (e.g., material increases or decreases)?