Chapter–by–chapter aids: Appendix B
B-13. The factor method of forecasting tries to forecast sales by finding a relationship between the
company’s sales and some other factor (or factors). For example, sales lumber, brick and other
materials used in residential construction are often related to the interest rate for home
mortgages. Also, see the discussion of the Sales & Marketing Management Survey of Buying
Power and related discussion in section “Forecasting Company and Product Sales by
Extending Past Behavior.”
The population of the city of Boulder (97.1 thousand) is only 65.6% of the population of
Lakewood (148.0 thousand). Therefore, the effective buying power for Boulder
($2,480,204,000) compared to that for Lakewood ($3,451,207,000) is smaller as would be
expected because of the population difference. But let’s take a closer look. If we go a step
further and consider the effective buying power per capita in each location, we discover that
(on a per capita basis) the effective buying power for a Boulder resident is actually higher than
It becomes clear that this sort of difference can be meaningful when we look at retail sales. In
contrast to the case with EBI, the total retail sales for Boulder ($2,147,663,000) are higher than
for Lakewood ($2,065,827,000), even though Boulder has the smaller population. When we
consider retail sales per capita (by dividing these figures for retail spending by the respective
populations of each city), we see that residents of Boulder spend significantly more
(a) Prepared cereals: If we look at food sales for the two cities, we can see that Boulder’s
figure of $439,133,000 is much higher than Lakewood’s figure of $297,529,000 (even though
there are fewer people in Boulder doing the spending). This tells us that residents of Boulder
spend significantly more for food than residents of Lakewood. If we go a step further (as
above) and calculate per capita figures, we can see that Boulder residents are spending 125%