Time Reversal Test requires that the product of P_{01} (price index number computed time backward) and P_{10} (price index number computed time forward) should be equal to one [1]; ie P_{01} × p_{10} = 1.

Factor Reversal Test requires that the product of P_{01} (price index number) and Q_{01} (quantity index number) should be equal to the net changes occurring in between the current year and the base year (V_{01})

ie. P_{01} × Q_{01} (Except the factor 100)