ROI or Return of Investments is a percentage of your budget spent on influencer marketing returned to you as Earned Media Value. In Media Plans you can compare every influencer that you plan to involve in the influencer campaign by ROI and EMV to find whose outcome most probably would be better.
By default ROI is based on estimated budget. However, if you know the real price, you can change the value accordingly. In this case ROI will be calculated based on real budget.