The prediction, released on Wednesday by PollWatch2014 - a VoteWatch Europe initiative partly funded by the European parliament - suggests that the parliament's S&D group is currently ahead of the EPP by just four seats.
The new PollWatch2014 forecast, the third so far in the run up to the European elections in May, suggests that the S&D group will finish with 215 seats in the new parliament and the EPP group - currently the largest in the assembly - will end up with 211 seats.
The results, say the group of political science researchers - Kevin Cunningham, Simon Hix and Michael Marsh - are based on the latest opinion polls from across the EU member states.
Their research also suggests that the EPP's candidate for European commission president Jean-Claude Juncker is likely to have more support in the new parliament than the S&D candidate Martin Schulz.
"In a run-off between Juncker and Schulz it seems reasonable to assume that the EPP, ALDE, ECR, and the Czech ANO (who are likely to join ALDE) would support Juncker, and together these groups add up to 323 MEPs", said professor Simon Hix.
"On the other side", he added, "if we assume that the S&D, GUE, and Greens/EFA support Schulz, then he would be backed by 311 MEPs. The big question is: will all these groups hold together in support of Juncker or Schulz? And what will the other 117 MEPs, in EFD and the non-attached, do?"
"As we get closer to the election, the battle lines between the lead candidates may become clearer. Nevertheless, EU governments may still try to impose their own candidate for commission president on the new European parliament, and this may be easier to do if neither Juncker nor Schulz commands a clear majority after the election."