MIAMI (JTA) — Fueled by KitKats and Cherry Coke, some two dozen people sit hunched over stacks of questionnaires in a windowless conference room in Miami, a phalanx of 1980s-era push-button telephones in front of them.

It’s the first day of work on a new survey of Miami Jews, and operators are having a hard time finding cooperative respondents.

“To you personally, is being Jewish, 1, mainly a matter of religion; 2, mainly a matter of ancestry; or 3, mainly a matter of culture?” a surveyor asks.

Ira Sheskin, the go-to man for Jewish communities that want to count their Jews, is overseeing the work. A professor of geography at the University of Miami, Sheskin is now on his 43rd Jewish federation population study, and he’s got it down to a science.

He has found that subjects are much more likely to talk if the interviewer is female. Because of the unique background of Miami Jews, Sheskin has hired interviewers who speak six different languages. Those with some fluency in Judaism offer certain advantages, such as the ability to discern when a respondent has misunderstood a question about whether they keep two sets of dishes to be about kitchenware rather than Jewish observance.

For the Miami survey, Sheskin has brought some of his veteran interviewers with him: Two women from Pennsylvania who have worked with him twice before and his octogenarian mother-in-law, who sits in a corner dutifully dialing numbers. His son and wife are helping out, too.

“When you get someone on the phone who is cooperative, it’s actually a very interesting process that both the respondent and the interviewer benefit from,” says Sheskin, 63, who did his first large community study in 1982, also for the Greater Miami Jewish Federation. “You hear some fascinating stories in these interviews, and you realize how inconsistent some people are.”

The last time the Miami federation took a census, in 2004, it found 113,000 Jews in Miami-Dade County. A lot has happened since: Hundreds of Latin American Jewish families from Venezuela, Mexico, Argentina and elsewhere have immigrated. The economic crisis and real estate bust of 2008 hit the state hard, slowing domestic migration to Florida for several years. The Orthodox community in Miami Beach appears to have grown. Old people died. Babies were born.

“The change in the complexion of the population has been really dramatic,” says Jacob Solomon, CEO of the Miami federation.

But without hard numbers, no one knows exactly how dramatic. That’s where survey data come in.

The new study, whose results are expected to be released this fall, will provide not only demographic data — country of birth, age, number of children, education level, religious denomination, Jewish observance level and more — but also take the pulse of community members on such issues as their emotional attachment to Israel, frequency of synagogue attendance, the importance of being Jewish to their lives and what sorts of Jewish activities they do.

In all, there are 151 possible questions, culled from past surveys and refined through 15 focus groups, four federation committee meetings, and discussions between Sheskin and federation leaders. About 80 percent of the survey is identical to Miami’s last one, in 2004.

These kinds of population surveys are meant to help Jewish agencies and institutions plan for the future. If, for example, the number of Jewish households with young children is falling in a particular city, it may put the local JCC’s expansion plans on ice. A question in the Miami survey about the newspapers read by respondents will help guide the federation’s newspaper ad spending. A survey Sheskin conducted years ago in nearby Broward County helped a Reform synagogue in Fort Lauderdale figure out that it was better to refurbish their old building than erect one 2 1/2 miles away, where it turned out few Reform Jews lived.

“There’s no question in my mind that these types of results provide data to federations that allow them to do better planning,” Sheskin told JTA. “I’ve never seen a federation that doesn’t want to do a study. Finding money is always the issue.”

This study is costing the Miami federation about $300,000.

“We allocate over $20 million per year — that’s $200 million over 10 years,” said Solomon, the federation CEO. “So to spend $300,000 once a decade to help guide the wisdom of committees and boards and agencies and synagogues as to how spend their money seems like a good investment.”

There’s a certain rhythm to survey taking. First, operators cast a wide net, calling number after number on Random Digit Dialing lists Sheskin has generated with local area codes. Finding Jews among respondents is a little like finding needles in a haystack, but it’s not an idle exercise. The early phone calls — probably about 7,000 of them — help calculate the number of Jews as a portion of the total population.

Operators then start zeroing in on the Jews, culling numbers from lists provided by Jewish institutions, including cellphone numbers with non-Florida area codes. Interviews usually take 15-17 minutes to complete.

Twenty years ago, the work was more straightforward. But telephone surveying has become more difficult due to the decline of landlines, the rising number of locals with non-local cellphone numbers and the propensity not to answer calls from unfamiliar numbers.

In the Miami survey, every number gets four tries, and interviewers call back those who specify a more convenient time to talk. In an effort to boost cooperation, the federation has taken out advertisements in local media and mailed thousands of postcards alerting community members they might be calling.

The goal is to get a sample size of roughly 1,800 Jews — enough respondents not just for the overall picture, but also enough to learn about subgroups: Holocaust survivors, Latin Jews, Israelis, retirees, parents. In all, the calling period will probably last five weeks. Interviewers work four-hour shifts spread over 12-hour days, earning $18 per hour.

Then comes the work of entering and crunching the data — Sheskin’s interviewers record answers by hand — and months of study. By fall, the survey should be ready to make news.

“Even if everybody doesn’t respond, and even if things aren’t perfect,” Sheskin says, “you still get a pretty good idea of what the Jewish community looks like.”