A poll carried out by Dialogue the day after the Labor chairmanship vote (Monday 13 September 2011) and published the following day shows that Israel’s two largest parties (Kadima and Likud) are losing strength. If MK Yacimovich leads Labor in the next elections Likud would win with 25 seats and a 64-seat right wing coalition; Kadima and Labor would have 22 seats each. If MK Peretz leads Labor in the next elections, Likud would win with 24 seats and own a 65-seat right wing coalition, with Kadima edging out Labor 24 to 18. It would appear that Likud and Shas are losing 3-4 seats to the other right leaning parties, while Kadima is losing seats to Labor and Meretz on the left. The poll has a representative sample of 482 likely voting Israeli adults, and the statistical error is about 4.5 percentage points.
If elections held today (expressed in Knesset seats)
Current Knesset seats in [brackets].
22 24 [28] Kadima
25 24 [27] Likud
22 — [08] Labor headed by Shelly Yacimovich
— 18 [08] Labor headed by Amir Peretz
15 16 [15] Yisrael Beitenu
09 10 [11] Shas
09 09 [07] Merger of Jewish Home and National Union
06 06 [05] Yahadut Hatorah/U.T.J.
04 05 [03] Meretz
00 00 [05] Ehud Barak Independence Party
08 08 [11] Hadash, Ra’am-Ta’al and Balad combined.
Jeremy's Knesset Insider 
Any idea why the polls have such different results? The primary?
The poll shows that the Labor chairmanship election has brought back some support for the party. It also shows that many people who would vote for a Yacimovich Labor would not vote for a Peretz Labor.
New Labor leader Yacimovich: Time has come for change (Jpost)
The Knesset is going to assume more of a civil service role in the near future. Most of the great existential questions of policy can be decided by another chamber. There was no Knesset during the 420 years of the Jewish Monarchy.