The sales funnel metaphor is somewhat misleading; in real life, the process never goes as smoothly as liquid down a funnel. In the last decade, digital marketing, artificial intelligence (AI), and CRM have drastically changed the process of converting new leads into customers. Given this, it’s increasingly important that business-to-business (B2B) sales and marketing teams are aligned in their views on a sales funnel strategy and lead generation as a whole.
You should be looking at these metrics all the time so you can assess whether you're slipping in any one area ... because you don't want to suffer a blip in your funnel. If your funnel develops a clog or hole somewhere along the way -- and it will, it's only natural -- you need to be able to identify it and fix it to keep your sales and marketing machine efficient. And if you are working with multiple different types of leads, these metrics should be considered for each segment of lead, too, so you know if some segments are more valuable to your business than others (or, even better, if some segments have more potential than you once realized)!
Probability to close. Even if your sales team has hundreds of high-value leads in the pipeline, salespeople may not be successful in winning a majority of those opportunities. Estimate how likely each lead is to convert into a customer based on your team’s conversations with them, their current stage in the sales pipeline, and other criteria that signal their eagerness to strike a deal. 

sales funnel diagram

Transacted: A sale has transpired when a contract is signed by both parties. From a salesperson’s perspective, the fulfillment of the contract is the responsibility of other parts of the organization, and the salesperson can now focus on the next opportunity. In the case of early-stage start-ups, however, frequently the person that sells is also involved in fulfilling the contract. A signed contract can be booked as revenue from an accounting perspective.

sales funnel stages