Demographics

Three types of projections were prepared as part of the Little Rock School District Facilities Master Plan Study – population, district-wide, and school-by-school. The following methodology was used in the generation of these projections.

Methodology

District-wide Projection – The cohort survival method was used to generate a new demographic projection for the LRSD.  The term “cohort survival” refers to the factors that affect individual age groups within the population. Demographic projections are based on a simple equation:

 Known population + births – deaths + persons moving in – persons moving out = Projected population

The first three (3) factors are known and can be verified.  Based on the Census we know, to the best extent possible, how many persons were living in Little Rock in 2010.  Since then, we know how many children were born and how many deaths occurred.  The migration factor…persons moving into or out of the area…is difficult to quantify.  The level of migration to be reflected in the projection is clearly the “art part” of demographics.

The start of this method is to divide the district population into distinct five-year [5] increment age groups (cohorts).  Therefore, the population of the district was divided into those persons age 0 to 4, 5 to 9, 10 to 14, etc.  Due to the small size of the final cohort, persons age 85 and over are considered as one cohort.

Using a combination of the annual fertility and mortality rates for each cohort, the population is “aged” each year throughout the planning period.  The fertility and mortality rates are taken from vital statistics from the State of Arkansas Department of Health.  It should be noted that this information is compiled based on the address of the person, not where the event occurs.  Thus, a birth to a mother from a particular county in Arkansas is reported as part of the statistics for that county regardless of where the birth actually occurred.

As stated, population changes are also affected by migration into and out of the area.  Traditionally, this is the most difficult factor to assess.  The level of migration was considered using a key source of data.  The IRS geocodes individual income tax returns by the social security number of the primary filer.  Geocoding is the process of defining the exact latitude and longitude of an individual address.  This process establishes the location of the home from which the return was filed.  The following year the location code of the primary filer is compared to the previous year’s location code.  Tables of outflows and inflows by county for each state are developed.  Again, this represents macro-level data that is useful for spotting general county-wide trends.

In addition, migration is affected, in large measure, by development patterns. The attraction of a new employer or the expansion by an existing employer that results in the creation of new jobs often results in a net in-migration to an area. The construction of new housing will also affect migration. Much of this information is based on data supplied by the City of Little Rock and Pulaski County.

Whenever possible, as much of this information was used to augment the cohort survival method.  The result was the development of a 10-year demographic projection for the population residing in the Little Rock School District.  While interesting and important, the annual survival ratio from one cohort to the next is primarily done to provide needed information, especially about births, upon which future kindergarten enrollment relies.

Enrollment Projection – Following completion of the district-wide population projection, the next step was to develop a grade-to-grade enrollment projection for the District as a whole as well as each school. The steps in generating an enrollment projection include:

  1. Kindergarten enrollment – The projected number of kindergarten students for the next ten years begins with an analysis of the actual number of births that occurred in the past as compared to the number of students enrolling in kindergarten five years later. Data on actual births from the State of Arkansas Department of Health were used. Since information on actual births is only available through the year 2012 the projected kindergarten enrollment using that information was generated to the year 2017. From that point until the end of the ten year planning period kindergarten enrollment was projected using linear regression. That combination provided projected kindergarten enrollment through the 2023-24 school year.
  2. Grade-to-grade survival ratios – The ratio, expressed as a percent, of the number of kindergarten students in one year who matriculated as first graders the next year was calculated. This was done for each grade level using ten years of data.
  3.  Apply the ratios – By multiplying the number of kindergarten students enrolled this year by the average ratio of the number of kindergarten students moving to first grade each year for a ten year period provided a projected number of first grade students in the 2014-15 school year. This application of ratios was done for each grade level for the ten year period to produce a district-wide enrollment projection.

Once the district-wide enrollment projection was completed the next step was to generate individual projections for each school. A similar procedure was followed.

  1. Kindergarten enrollment – The total number of projected kindergarten students was developed for the district-wide projection. That total number was divided among each elementary school with an adjustment for the number of women of child-bearing age in the location of each school.
  2. Grade-to-grade survival ratios – Just like the district-wide projection, the ratio between the number of students in a grade one year that move to the next grade the following year was generated.
  3. Apply the ratios – As with the district-wide projection, the ratios were applied to each grade for the ten year period to generate an enrollment projection for each school.

Using this methodology projections were developed for the Little Rock population; student enrollment for the entire District; and, future enrollment for each individual school.

Demographic and Capacity Methodology - 6/04/14

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