BERLIN (Reuters) - Doubts about the reliability of opinion polls arose after unexpected election results in Britain and the United States last year, but German pollsters say their methods and domestic circumstances mean Germany should be immune to election shock next month.

FILE PHOTO - Election volunteers prepare postal votes to be counted at 1600 gmt with all other ballots in the German general election (Bundestagswahl) at the Messe in Munich September 22, 2013. REUTERS/Michaela Rehle

German opinion surveys have been precise in the past because party allegiance is high, Germany uses proportional voting and several large and well-funded polling organizations compete with each other, political scientists and polling institutes said in interviews on Tuesday.

That is no guarantee of success for the September election in Germany, in which Chancellor Angela Merkel wants to win a fourth term, but those factors contribute to a sense of “it can’t happen here” when Brexit and Donald Trump are mentioned.

“That poll forecasts in Germany are more accurate than in many other countries has a lot to do with German conditions,” said Lutz Hagen, communications professor at TU Dresden University.

“First, people have strong party ties,” Hagen said. “Also, it’s rarely a personality contest as people vote for parties, not candidates. It’s also a proportional system rather than winner-takes-all. Yet, volatility is increasing here, too.”

Pollsters reckon 30 percent this year will not make up their minds until shortly before or even on election day, Sept. 24.

Still, declining unemployment, solid growth and a satisfied populace have given Merkel’s conservative party a poll lead of about 14 percentage points over the center-left Social Democrats (SPD) and candidate Martin Schulz.

That could still change. The SPD made strong comebacks in 2002 and 2005, but many pollsters consider it unlikely.

“Some elections are hard to forecast,” said Manfred Guellner, managing director of Forsa, who accurately predicted a razor-thin SPD-Greens’ comeback win in 2005 against long odds.

“But the constellation for the decision this time is much clearer. The SPD has little authority and a weak candidate. It’s easier for pollsters to capture the mood this time around.”

Matthias Jung, head of Electoral Research Group (FGW), said polls are merely momentary mood snapshots. “Some people sometimes expect too much and read too much into them,” he said.

But he agreed polling is a serious business in Germany, where a high degree of accuracy is expected and deep-pocketed public broadcasting networks invest enormous sums in polling.

Jung’s exit polls, for instance, are based on 50,000 interviews and broadcast as soon as polls close. They are usually spot on with results published hours later.

“No other country in the world has better exit polls than Germany,” said Richard Schlinkert, founder and owner of dimap, which is part of the Infratest-dimap institute. It will do 100,000 exit poll interviews on September 24.

“They’re world class, like the German autobahns. It’s a mixture of organization, methodology and experience.”