Contributed by Great Reach Communications editor, Heidi Tolliver-WalkerMany just look at response rate.  But here are four metrics they need to know. Notice that response rate is only one of them.1. Response ratesThis is a good first measure of the quality of your customer's print campaign. If the response rate is high, they (and you) have done a good job with the mailing list, the design, and the incentive. Recipients liked it enough to take action.2. Conversion ratesOnce people respond, it's up to your customer to convert those leads to sales. This is up to their sales team, website, or customer service people. If the conversion rate is low, this is an opportunity to help your customer identify and fix the problem.3. Cost per saleOne thousand people can respond to a marketing campaign, but to make money, each sale must generate more money than it costs to generate.4. Lifetime customer valueIf you gain a new customer through a marketing campaign, that customer will generate more revenue than just one sale.  He or she will continue to bring in sales for years to come. Even if it costs more to acquire that customer (such as through personalization), if each customer has a high lifetime customer value, it's worth it.Understanding what these metrics are and how to use them is part of the value you can offer as a trusted marketing partner. Then you can use these metrics to improve their results and keep that customer relationship strong.