There few piece of information more valuable in selling than knowing whether or not a particular prospect is likely to buy from you. Most of the time, however, you can tell whether or not a prospect is “hot” based upon how that particular prospect got into your sales pipeline.

Here are eight basic types of “sales leads,” in order of the likelihood that he or she will buy:

1. Unsolicited referral. An existing customer who, without your prior knowledge, convinces his or her colleague to contact you.

2. Solicited referral. An existing customer who, at your suggestion, convinces his or her colleague to contact you.

3. Social contact. A person whom you've met at an industry or social event and who shows an interest in you and your offering.

4. Cross referral. A person responsible for selling inside another company who asks you to become involved in an opportunity.

5. Social media contact.  A person with whom you are communicating on a social media network, such as Facebook or LinkedIn.

6. Website visitor. A person who has visited your website and shown some kind of interest in your offering.

7. Internet contact. A person who turned up in a listing on a search engine of companies and job titles.

8. Contact from a purchased list. A person who is on a list of people who supposedly are interested in your type of product.

Everything else being the same, a prospect generated through an unsolicited referral is at least 10 times more likely to buy from you than somebody off a purchased list.

The reason is simple: trust.

In most selling situations, the primary barrier to buying is a lack of trust.  When a colleague tells a potential buyer that you’re a good guy and worth buying from (i.e. an unsolicited referral), you’re halfway to making the sale.

The same thing is true, to a lesser degree, for other kinds of sales leads.  In terms of creating trust, for example, a face-to-face meeting (as in a “social contact” lead) at a conference trumps a series of online interactions (as in a “social media contact” lead).

Similarly, a prospect who's taken the time to examine your website is more likely to trust you (when you call to follow up) than if you cold-call them out of the blue.

Needless to say, it's a lot easier to build sales through referrals than through cold-calling, which is why a major goal of every sale should be to create a strong relationship.  There is simply no easier way to sell than have your customers do it for you.

Want to know how get your customers to sell for you?  Check out this column: 3 Tricks to Get Great Sales Referrals.