In most cases, cardholders submit a dispute in order to initiate a chargeback, and nothing more. In this circumstance, there is no need to calculate a first win rate and a final win rate. This is because the chargeback stage was the only stage where a dispute was processed.
However, some analysts and merchants regularly respond to disputes that went to second chargeback or pre-arbitration (which is the same stage). This means they respond to disputes in two different stages. This allows someone to calculate their win rate from the chargeback stage (i.e., the first win rate) and their win rate from the second chargeback/pre-arbitration stage (i.e., the final win rate).
The reason why there will be two win rates is to compare your team's success rate in different dispute stages. This allows you to compare their results and to plan accordingly to improve your win rates.
For example, an analyst will calculate their win rate (see 'How do I calculate my win rate?') from two dispute stages: the chargeback stage and the pre-arbitration stage.
Within the last 30 days, the analyst found out the team's first win rate, in the chargeback stage, was:
Within the last 30 days, the analyst found out the team's final win rate, in the pre-arbitration stage, was:
So, it seems the analyst's team earned a final win rate that is 24.2 percentage points lower than their first win rate. E.g., they had better success in winning against disputes in the chargeback stage, but not in the pre-arbitration stage.
After some follow-up research, the analyst's team will develop a strategy to improve their win rates.