Before revision: The bio-index model advises the challenging party (i.e., the Republicans ) to nominate the candidate with the highest index score relative to the index score of the incumbent president (i.e., Obama).
After revision: The bio-index model advises the challenging party (i.e., the Republican PartyBarack ) to nominate the candidate with the highest index score relative to the index score of the incumbent president (i.e., Obama).