National and international businesses, too, will be eager to study the Chinese census data. These companies need to understand the size, geographical location and socio-demographic make-up of the Chinese population in order to decide where to locate facilities and how to deliver goods and services.

Finally, census data can be used as an educational tool, allowing students to compare their local communities with others in their country and with other parts of the world.

Although census data are very useful for a modern society, all countries, including China, face major challenges when conducting a modern-day census. In addition to the logistical planning for what in many countries is their largest peacetime mobilization of a temporary workforce, a successful census depends on the cooperation of every household to provide complete and accurate information.

One challenge is simply to find people at home who will provide the required information. This may be a particular challenge in large Chinese urban areas where, in some cases, citizens may be reluctant to provide certain information for fear it might be used against them.

China's census is also complicated because of the presence of migrant workers - those tens of millions of undocumented workers who have left the countryside for jobs in urban areas and now live on the outskirts of large cities. This information is very sensitive because of the traditional hukou system and the implications it has for residents' entitlement to services.

China's family planning policy might be another point of concern for those families reporting more than one child. Although these issues are very sensitive from a respondent's point of view, it's crucial to obtain an accurate count of the migrant population and number of children for future planning purposes.

As with any countries' census efforts, China's statistical agency and government must stress that the census information will be used at an aggregate level for research purposes only. They have to ensure that personal information collected in the census will not be used at the individual level to track or question an individual's circumstances.

The first results from the Chinese census are expected in April 2011. There is no doubt that the new data on China's population will be of interest to all parts of the world. Along with the business community and my fellow demographic researchers, I eagerly await the portrait of China that will emerge from this extraordinary undertaking.

The author is senior vice-president and chief demographer of Environics Analytics, Toronto, Canada.