The steps outlined below are meant for B2B organizations that use a sales force.
Assumption: You’ve already narrowed down your list of marketing channels. If you haven’t, do your homework first and then follow these steps.
Step 1) Write down all the marketing effort / channel options and figure out:
a) The monthly cost
b) Your “expected” monthly return on the investment
This is hard but you have to start here.
Step 2) Calculate for each channel/marketing effort:
a) Average conversion rate of the lead * max monthly quantity of leads (that convert at the rate to the left) * average $size of the converted lead = avg. monthly revenue
b) Average monthly rev. / your monthly investment = ROI for the channel
Step 3) Compare all the ROIs for all of the channels in a nice table. Each marketing effort/channel should be a row.
Step 4) Add up the “monthly rev” for each (starting from the top row) until you hit your monthly goal.
If you can’t even get broad data that covers this, then you either need to press the person responsible for that marketing effort or realize that you’re making a decision without enough information.