1. ARITHMETIC INCREASE METHOD
Presented by Group 3
Members:
GUNGOOSINGH Sonali
HUNG CHEONG LAN Kriss
PIERRE-LOUIS Antoine
QUATRE Rudolph
RAMDAWOR Nitish

2. INTRODUCTION Simple method of population forecasting.
Based on the results of at least two censuses.
Results obtained from extrapolation of values from latest enumeration.

3. HOW METHOD WORKS?
Assumption : Present population density changes uniformly with time. 𝑑𝑃 𝑑𝑡 =𝑘 Where P – population at any given time t k – constant rate

4. HOW METHOD WORKS?
Arithmetic Increase Method Equation: 𝑃 𝑓 = 𝑃 0 +𝑘𝑡 Where Pf – future population after time t (years) P0 – present population k – constant rate

5. Population (thousands)
EXAMPLE
Population of Reduit from following census figures:
Year
Population (thousands)
1942 60
1952 65
1962 63
1972 72
1982 79
1992 89
2002 97
2012
120

6. EXAMPLE Year Population Change 1942 60 1952 65 65 – 60 = +5 1962 63
= -2
1972 72
72 – 63 = +9
1982 79
= +7
1992 89
89 – 79 = +10
2002 97
97 – 89 = +8
2012
120
120 – 97 = +23
Total
+60
Average (k/yr) =

7. EXAMPLE
P0 = 120,000 k = ≈ +860 In 2022 : t = 10  Pf = 120,000 + (860 x 10) = 128,600 In 2032 : t = 20  Pf = 120,000 + (860 x 20) = 137,200 In 2035 : t = 23  Pf = 120,000 + (860 x 23) = 139,780 In 2042 : t = 30  Pf = 120,000 + (860 x 30) = 145,800

8. DISCUSSION Simplest method of extrapolation.
Valid if approximately equal incremental increases are noted in recent censuses.
Method gives too low estimates with time.
Used for short term estimates only, i.e. ≯ 30 yrs
Can be applied to population of large cities.

9. THANK YOU!