Poll gives Chernovetsky convincing lead

Two media outlets quoting presumably the same polling results reported drastically different numbers in the race for Kyiv mayor. The reports conflict on whether incumbent mayor Leonid Chernovetsky’s rating is 34.6 or 47.2 percent. The numbers for number on contender Vitaly Klitschko cover a five point spread.
On May 6, Ukrainian News reported numbers from Ukrainian Sociology Service’s poll of 1,500 respondents that was conducted in two phases between April 19 and 30 and has an error margin of 2.6%.

Candidate	%
Chernovetsky	34.6
Klitschko	15.5
Turchynov	5.7
Omelchenko	4.1
Katerynchuk	3.9
Against all	2.7
Pylypyshyn	2.3
Tiahnybok	1.5
Horbal	1.2
Other parties	2.3
Undecided	15.5
Will not vote	7.9
Sums up to only	97

Poll of 1,500 respondents, April 19-30, statistical error: 2.6%
Source: http://uv.ukranews.com/k8/

Meanwhile, the same day a LIGABiznesInform correspondent reported slightly different numbers quoting respected sociologist Oleksandr Vyshniak, the head of Ukrainian Sociology Service.

Most notable is the 12.6% difference in support for incumbent mayor Leonid Chernovetsky. The spread on Klitschko is 5%.

Candidate	%
Chernovetsky	47.2
Klitschko	20.5
Turchynov	7.9
Omelchenko	4.9
Katerynchuk	5.7
Sums up only	86.2

Poll of 1,500 respondents, April 19-30, statistical error: 2.6%
Source: http://news.liga.net

That leaves 14% for the 72 other candidates, the undecided, against all, etc.

Who to believe?