What are the four factors that affect the ROI in the investment return computation model described in the chapter?

The four factors that affect the ROI in the investment return computation model are market return, interest rate, inflation rate, and credit spread.

These factors are characterized as follows: the market is defined by its mean return and volatility; the interest rate is broken down into initial rate, long-term average, mean reversion period, and rate volatility; the inflation rate includes average rate and volatility; and the credit spread consists of average credit spread and volatility. Together, these elements influence the overall return on investment.