Step 1: Determine Total Net Profit: Deduct the initial cost of the investment from the total forecasted returns generated over the asset's entire lifespan.
Step 2: Calculate Average Yearly Profit: Divide the total net profit from Step 1 by the total number of years the asset will be utilized.
Step 3: Apply the ARR Formula: Divide the average yearly profit by the initial investment cost and multiply by 100 to obtain the percentage return.
ARR Formula:
Advantages of ARR: Unlike simpler methods, ARR evaluates the entire profitability of a project over its full lifetime, allowing for a comprehensive comparison between different investment sizes using a standardized percentage.
Critical Disadvantages: The method relies heavily on forecasted profits which can be inaccurate, and it fundamentally ignores the Time Value of Money, treating profits earned in ten years as identical in value to profits earned today.
| Feature | ARR Advantage | ARR Disadvantage |
|---|---|---|
| Comparison | Easy to rank projects by % | Ignores initial risk of capital |
| Scope | Considers all net cash flows | Dependent on subjective forecasts |
| Strategy | Identifies long-term gain | Ignores the 'Opportunity Cost' |
Check Your Denominator: A common mistake is using 'Total Returns' instead of the 'Cost of Investment' in the final ARR calculation; always ensure you are dividing the profit by what was originally spent.
Rounding Consistency: In exam scenarios, always provide your answer to the requested number of decimal places and ensure the '%' symbol is clearly present to avoid unit errors.
Own Figure Rule (OFR): If you miscalculate the initial profit, continue the calculation with your 'wrong' figure. Examiners will often award marks for the correct method even if the starting number was incorrect.
Confusing Revenue with Profit: Do not use the total income generated as the numerator; you must subtract the investment cost first to find the net profit before calculating the average.
Neglecting the Timeframe: Forgetting to divide the total profit by the number of years will result in a 'Total Rate of Return' rather than an 'Average Rate of Return', leading to inflated and incorrect percentages.
Ignoring Alternative Returns: An ARR of 10% may look good, but if a simple bank account offers 12%, the investment is a poor choice due to the higher opportunity cost.
