Do a Comprehensive Demographic Study in 2011

• By Paul Abramson
• 03/01/11

According to the Chinese calendar, 2011 is the Year of the Rabbit. School districts ought to make 2011, the Year of the Comprehensive Demographic Study.

In school parlance, demographic studies essentially mean projecting the number of students likely to be enrolled in the district and individual schools next year and over a period of five to 10 years. The simplest and most effective way to do that is called the cohort survival method.

Cohort survival simply says, all things being equal, what has happened in the recent past is likely to occur again in the near future. So, if over the last three to five years your district has lost students going from kindergarten to first grade, cohort projection shows what would happen if the same trend occurred over the next few years. Likewise, if the district gains students entering high school or tends to have flat enrollment in the middle grades, cohort survival tells what would happen if that pattern was repeated. (Another key component is the number of children born in the district, available from most state health departments, and what percentage of those will enroll in kindergarten five years later.)

There are obvious variations — families move in or out or make different decisions; a non-public school expands or contracts. It is unusual for the projected number for every grade to come out exactly right (over 40 years, my firm was that lucky just once), but such cohort survival projections tend to be very accurate for a year or two, less accurate the further out they get. Done every year, they will keep a district on track for budgeting, staffing, etc.

A district can do this type of projection on its own, using a spreadsheet, though I would recommend using an outside demographer at least every few years to make sure no errors creep in to look for changes in trends that might go undetected, and to give the public confidence that the projections are not biased.

Comprehensive Demographic Studies
So why should 2011 be the year of the Comprehensive Demographic Study? The key is the word “comprehensive.” A Comprehensive Demographic study not only looks at the year-to-year changes in enrollment, it looks at what is happening in the district over a longer term, and with a wider perspective. Much of what is needed for that kind of a review is contained in U.S. Census data, and the 2010 Census, now available, provides the latest possible information.

Communities change over time. The level of income can go up or down, depending on the housing stock and the options available in neighboring communities. The average age of the population can change. Job opportunities and transportation options may cause people to move into your community or move out.

Communities gain reputations, sometimes deserved, sometimes not. Those reputations tend to stay long after the communities themselves change. The changes do not often happen overnight and even people living in the communities sometimes are unaware of what has happened. A Comprehensive Demographic Study gives a school district a chance to see those changes over a period of 30, 40 or even 50 years and to gauge how they have, or possibly will, change the school population and program now.

Changes in family size may be important. Tracking ethnic change over longer periods of time can add accuracy to projections. We worked recently in two communities about 100 miles apart. Both had growing populations. In each, over several decades, hundreds of members of different ethnic groups had taken up residence within the school district’s borders. In one community, virtually all of the children were sent to private religious schools. In the other, virtually all enrolled in the public schools. In both districts, family size was up but in only one did that translate to higher public school enrollment.

Districts can always look at Census data, but it gets old. In 2011, school districts have an opportunity to look at the new 2010 Census figures and the considerable fresh information that they can provide. With it, you can track the rate and direction of change in housing, births, ethnicity, jobs, population, age and much more in the last 10 years, see how it has changed over previous 10-year periods, project that into the future, and use it to create a model of likely change over the next decade — a model that can then be watched and tweaked as the years roll by.

Savvy districts everywhere will take advantage of the new Census information and make 2011 the Year of the Comprehensive Demographic Study.