When it comes to defining certain online measures, we need a consensus. But when it comes to defining engagement, one size does not fit all.

Discussions of standardized success metrics tend to get me up in arms, as I've written before. It wasn't until the iMedia Agency Summit opened that I fully understood why. Frankly, it's because the industry leadership doesn't seem to understand the difference between a measure and a metric.

There's a reason why I distinguish between the two. Metrics are composed of measures and are defined by advertisers and their marketing partners. There's often a good deal of strategic discussion around metrics -- what's important to consider during the process of planning a campaign, and what will define whether or not the campaign is successful.

Measures are the base components of metrics. Examples include "unique visitors" or "ad clicks." These are the building blocks that allow us to build metrics that can give us an understanding of how various opportunities compare to one another, or how campaigns impact our audiences. These often require a great deal of technical knowledge -- often at the code level -- to define.

I need industry leadership to help me define the measures. Leave the metrics to me and to my clients.

I need the various stakeholders (three- and four-letter organizations who purport to represent us in figuring this stuff out) to tell me that they have a measure for traffic to a site that's bulletproof and that takes into consideration the dynamic imposed by technologies like AJAX. I need this more than heady concepts or the definition of engagement. I need to know that we can agree on how to count ad clicks without leaving the methodology open for cheating or misinterpretation.

In short, I need you, stakeholders, to tell me how big an inch is and that its length won't change or be subject to interpretation. Don't even begin to think about giving me advice on how to hold the ruler or whether I should measure things horizontally or vertically before setting this standard.

In fact, I'd rather no one try to tell me there should be a standard definition of engagement at all. As a concept, engagement means different things to different people and it should be left up to strategists to decide how a site's engagement should be measured, what measures should contribute to an engagement metric, and what levels of engagement should be considered successful.

At the iMedia Summit, I learned that there are people who understand the role of an industry body that needs to certify measures quite well. Others? Not so much.

And that's why I believe that the debate over measurement needs to be refocused on the basics. My needs are as follows: 

• Clear definitions of measures
• Audits to ensure measures are consistent and not subject to interpretation or abuse

I do not need industry leadership to figure out which metrics are most appropriate to the planning or success measurement processes. That's where "one size fits all" doesn't work, and that's one of the places where organizations like mine add value for digital marketers.

Tom Hespos is the president of Underscore Marketing and blogs at Hespos.com.