If you liked what-if stories as a child, you’ll love multiple-scenario forecasts.
They start with a straight-line forecast in which you assume that your sales will grow by the same percentage next year as they did last year. Then you make up what-if stories and project their impact on your plan to create a variety of alternative projections.
At this stage of preparing your marketing plan, you need to put on your accounting and project management hats. (Perhaps neither hat fits you very well, but try to bear them for a day or two.)
Buildup forecasts are predictions that go from the specific to the general, or from the bottom up. If you have sales reps, ask them to project the next period’s sales for their territories and to justify their projections based on their anticipated changes in the situation.
To use the time-period forecast method, work by week or by month, estimating the size of sales in each time period, and then add these estimates together for the entire year.