ROI - Return On Investment setting is used to prevent bot from staking high amounts of money when trying to win small target profit. This setting is available in rules that use dutching logic and are designed to win target profit by placing Back bets on one or more runners e.g. Overall loss recovery, Dutching for target profit etc.
For example, if you Back single selection at price 1.5 with stake of £100 then you will get profit of £50 if bet wins and loss of £100 if bet loses. This means that our potential return on investment of £100 is 50%.
Table below shows return on investment for Backing single selection at different prices.
We can see that for same stake (investment) we are getting different profit as we are Backing at different price, which means that return on investment is different too.
Backing selection at small price obviously has smallest profit, that is small return on investment. If you do not want to risk high amounts of money to win small profit then you should set minimum ROI to high value, but if you are willing to risk high sums of money to win small profit then keep ROI at low value.
This setting is very useful when using "Overall loss recovery" and "Dutching for target profit (Back bets)" staking rules. Both rules are designed to place Back bets on one or more selections to win target profit. In many cases you do not know prices of those selections or number of selections at which bets will be placed, which makes Minimum ROI setting very useful.
Setting ROI to 50% would prevent loss recovery being added to your bets if potential return on invested money is less than 50%. Loss recovery would simply have to wait for better opportunity with higher odds to attempt to recover your loss by risking less money.
Same is for "Dutching for target profit" rule, that will skip betting on market if selection prices will not generate high enough profit to satisfy Minimum ROI setting.
For PLACE markets (or any other markets with more than 1 winner) Minimum ROI will not be satisfied in many cases, as prices are very low and ROI calculation is based on logic that only one runner can win, where at PLACE market there can be more than one winner.
If you decide to Back first four favourites in greyhound race that has total of six runners then return on investment will be very low, as you are Backing almost all outcomes that have any chance to win. Similar situations are when Backing horses or dutching correct scores at football.
You should test different Minimum ROI settings in simulation mode and try to find best ROI that works for your strategy. Each betting strategy is different and there is no best or optimal ROI value that works for all strategies.