This is an updated piece cross-posted from Eretz Acheret, with a new title.

This year’s decennial census of England and Wales may be the last of its kind, but if so, at a cost of $782 million, it will go out with a bang. For Britain’s Jews its loss could be very unfortunate. Data from a voluntary religion question, included for the first time in 2001, provided a fascinating and potentially invaluable snapshot of the Jewish population. The question is included again in the 27 March massive data gathering exercise and if Jews choose to answer in the same high proportion as last time, demographers will be able to identify trends and significant changes in the community’s profile which should be of immense value to those offering services to the Jewish population. And the same would be true for other religious groups.

The religion question is quite unique. It’s the only voluntary one in the entire census form. Completing all of the others is compulsory, a legal requirement. As far as I know, no other Western European country that conducts such a census includes a voluntary religion question. Some use alternative means to collect such data. For others, especially where there is a constitutional separation between church and state, asking such a question, even on a voluntary basis, would be seen as running counter to the country’s secular ethos.

Whether the government should be allowed to gather such information through a national census is always going to provoke controversy. Freedom of religion is a principle enshrined in the European Convention on Human Rights and should be a purely personal matter. One fear is that an unscrupulous government could use the data for discriminatory purposes of a negative kind. And this was one of the major objections raised by prominent Jewish figures and by strictly orthodox Jewish groups during the consultation that took place before the introduction of the question in 2001.

For those of us involved in promoting and undertaking social research on Jewish life in the UK and the rest of Europe, the objection of possible nefarious use was groundless. First, you weren’t obliged to answer the question. Second, the administrative safeguards against misuse were (and still are) watertight. Third, such a fear assumes a degree of fragility in Britain’s political system that simply doesn’t exist. Fortunately, most Jewish leaders and organizations welcomed the inclusion of the question and encouraged Jews to complete it. It is very unlikely that they would have adopted such a position in 1991, but a revolution in thinking about what the community needed to know about itself in order to survive and thrive, which occurred in the early 1990s, ushered in a golden period for survey-based data-gathering. And it was in the prevailing positive atmosphere that, excluding the strictly orthodox who largely avoided the question—and later came to regret what they did because it affected their entitlement to claim services from their local authorities—a far higher than anticipated proportion of the Jewish population completed it.

The most eye-catching piece of data from 2001 was clear evidence that the Jewish population in the UK was at least 10 per cent larger than current community-sponsored research had suggested—up to 330,000, rather than 280,000. Whether clear evidence of population trends will emerge from the 2011 data is by no means certain. While the major Jewish organizations are still encouraging Jews to answer the question, there is no longer such a positive attitude towards data-gathering on the part of Jewish leaders. Some question just how much use was really made of the data for serious and practical policy planning. But more important, a growing sense of insecurity has gripped some of the principal leaders and certain significant sectors of the Jewish population, fuelled by fears of antisemitism, Islamist terrorism and perceived hostility to Israel, such that there is probably less of an appetite to want to be open about Jewish identity. I may be—and I hope I am—wrong about this. And there is some evidence that the higher levels of Jewish assertiveness identified in social research from the 1990s and early 2000s have not dissipated to any great degree.

Another problem is that the community’s capacity to analyse the enormous amount of data that emerges from the census was significantly reduced in the mid-2000s, but steps to rebuild it have been taken over the last two years.

The truth is that the Jewish community needs accurate data about itself more than ever if it wishes to secure the continuity of Jewish life in Britain. Knowledge is power, especially so in the internet-based social-networking age, and permanent but flexible research expertise is fundamental, though this fact is not fully appreciated because of leadership short-termism and excessive preoccupation with external threats.

If the decennial national census is scrapped—and the main reason would be that the data are almost out of date by the time that the first analyses are produced; government and local authorities need much more current information to be able to plan vital services for the entire population—and Jewish leaders again lose interest in research, the task of planning social, educational and cultural provision will become that much harder.

But new ways of gathering data are being developed all the time, so in theory the loss of the national census and with it the data that would emerge from the voluntary religion question, could undoubtedly be very substantially mitigated. It all depends on how much the community’s leading researchers and research organizations assert themselves—Dr David Graham, head of social and demographic research at the Institute for Jewish Policy Research, argued strongly in the Jewish Chronicle that the census is ‘a vital tool of communal service provision’—and how imaginative and far-sighted new generations of Jewish leaders will be.