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APPENDIX A <br /> POPULATION PROJECTIONS: EXPIANANTION OF METHODOLOGY <br /> Two extrapolative population projection methods were used: L1NAVE or <br /> linear extrapolation and EXAVE or exponential extrapolation. <br /> The LINAVE method assumes that population will change by identical in- <br /> crements in each interval of future time and is calculated based on the <br /> average population change in decades. This method is considered to be <br /> the most accurate method for moderately growing townships, at a rate <br /> of up to 25%. <br /> The EXAVE method assumes that population will occur at constant percent- <br /> - age rates over time and Es cb,Iculated based-on the average rate of tlopula- <br /> tion change in previous decades. This method is considered to be the <br /> most accurate method for rapidly growing Tabwnships ,at a rate of more <br /> than 25%, and Townships with less than 5000 inhabitants. <br /> The equations used in the EXAVE and LINAVE methods are described below: <br /> Linear Extrapolation (LINAVE) <br /> Pt - Pi <br /> 71771, <br /> Exponential Extrapolation (EXAVE) <br /> n = <br /> -Pt n/(t-i) <br /> Pt Pt <br /> Pt-i <br /> Where: P = population <br /> t = terminal year of base period <br /> i = initial year of base period <br /> n = number of years to projected year <br /> I SOURCE: Andrew M. Isserman. "The Accuracy of Population Projections <br /> for Subcounty Areas". Journal of the American Institute of <br /> Planners. July 1977. Vol. 13. No. 3. Pps. 2 7-259. <br />