The field worker matches the villa at 5 El Balu'a Street with a building survey map, scribbles a number in blue crayon, and then offers a brief introduction to the homeowner on what the counting means.

"I'm a representative of the Palestinian Central Bureau of Statistics, and we're doing preliminary work for the census," says Raniah Haseebah, a youthful, bright-eyed statistician. "I'm giving you this questionnaire."

Palestinian survey-takers this month started going house to house for a tally that is likely to loom large over the renewed peace negotiations with Israel. But the credibility of the new census, which will also document the damage from the second Intifada in 2000, faces obstacles ranging from Israeli restrictions on pollsters' movements to charges of political meddling from the Israeli right to the skepticism of the respondents themselves.

In the decade since the inaugural Palestinian census of West Bank and Gaza residents, the politics of numbers has inspired support among Israelis to withdraw from most of the Palestinian territories. But since that last census, the trepidation among Israeli Jews to return the country to its narrow borders prior to the 1967 Six Day War has been trumped by fears of a "demographic problem": Israelis may one day wake up to find themselves a minority in control of a Palestinian Arab majority.

"At face value, a census is neutral, and it's in the interest of everyone to have it. But there are also political considerations," says Hebrew University demographer Sergio Della Pergola. "Demography plays a crucial role in the perception of the future and peace negotiations. The numbers count."

The Palestinian Central Bureau of Statistics (PCBS) counted 2.6 million West Bankers and Gazans in 1997. Mr. Della Pergola expects the number to have grown to about 3.4 million. And even though Israel's population is 7.1 million, approximately one-fifth are Arab citizens and residents who identify as Palestinians. With a fertility rate that outstrips Jewish Israelis, Palestinians are expected to draw even in the not so distant future.

Still, the pressures of surviving the daily clashes and Israeli security limitations have spurred an exodus from the West Bank and Gaza – a migration for which the current census is expected to offer the first definitive figures.

"It's extremely important," says Palestinian pollster Khalil Shikaki. "The Intifada has seriously affected population figures. We don't know how many people left or how many people returned. No doubt this will be a major factor in the debate."

And yet, collecting the data means a number of practical hurdles for Palestinian census-takers. Though one statistics bureau official described the count as a "national project," others admit field workers have met reluctant participants in politically contested areas like the West Bank city of Hebron and East Jerusalem.

Mahmoud Jeradat, the executive director of a census operation that includes 5,500 workers and costs $8.6 million, says he was arrested in 1997 for trying to conduct the census in Jerusalem. This year, he can't get a permit to oversee the Gaza operation.

"I don't want to stand here and claim that everything is going fine and everything is going perfectly," he says. "This is something professional and technical, but in this area of the world it's political."

The survey is also shaping up as a test of the Palestinian Authority to prove to a constituency disillusioned by widespread chaos and Hamas's takeover of Gaza that the Ramallah government can function. And because the statistics bureau is seen as a function of Mahmoud Abbas's Fatah party, there's always a risk that Hamas in Gaza could decide to interfere in the effort.

Statistics bureau officials say that questionnaires delivered today will be picked up and tallied in December, and published next year.

While the Palestinian statistics bureau has won praise from Israeli and international statisticians, the agency has been charged with voodoo demographics by a group linked with the Israeli right-wing.

In an article published by Bar Ilan University entitled the "Million Person Gap," researchers argued that the Palestinian statistics bureau exaggerated its population figures for 2004 by 1.3 million. Della Pergola says the article's conclusions are not supported by the evidence and notes that the authors are not professional demographers.

Yet analysts say that, ultimately, Palestinian negotiators are unlikely to marshal the demographic trends as leverage in negotiations. Such arguments would imply that Palestinians would accept a unified state with Israelis – a scenario rejected by the Palestinian national movement, says pollster Mr. Shikaki.

But many believe that in the absence of a peace treaty in the short term, the shifting demographic balance, coupled with a new uprising and a Palestinian political gridlock, could also render the two-state solution impossible. If the results of the census show a rapidly expanding Palestinian population, Palestinians may rally behind a shared, binational state in which they would have the majority.