By this point in marketing history, it’s fairly unanimous that “last click” marketing attribution—giving all the credit to the ad that leads immediately to the conversion—is sub-optimal analytics. But while no sophisticated marketer would rely on last click alone, the spirit of last click is, unfortunately, alive and well.

Essentially, last click attribution is just one example of a wider problem. Marketers have a lot of readily-available data about a portion of the purchase funnel—and a lot less data about the other factors that drive consumers to a decision. In last click, that manifests itself in focusing analytics on one touch point, like email or search. But there are many more ways marketers still miss the full array of consumer decision drivers, and end up giving ads more credit—or more blame—than they really deserve.

For a few examples of more sophisticated “last click” problems, read on.

1. Not looking beyond the ad

There are a lot of things that drive consumers to act—or that drive them away—that have nothing to do with marketing. If consumers buy more umbrellas when it rains, less gas when prices are high, or refuse to buy sub-par products, it’s quite possible that advertising had little to do with the decision.

In theory, that’s obvious. But in practice, external impact can be a lot harder to identify than you might think. And so it’s endlessly common for marketing campaigns to get the credit—or the blame—that really ought to go to those external factors. That’s why it’s critical to investigate not just what marketing factors are driving purchase decisions—but what non-marketing factors are driving customer activity, too.

2. Ignoring the halo effect

Say you’re a small sneaker brand running three ad campaigns concurrently. One ad is for your basketball line, one is for your running shoes, and a third is for the parent brand. Your data shows that your running shoe ads perform very well. But should all the credit go to the running shoe ad—or should some go to the other two ads as well?

If you’re active enough in marketing, it’s likely that consumers have seen a lot of your ads. They’ve seen ads for your multiple products. They’ve seen ads for your brand. They may even have associations with your advertising that go all the way back to childhood. These are powerful influences that will inevitably impact your ad effectiveness. And if you’re not accounting for the impact these “halo effects” have on your message, you’re potentially misreading the real contribution any given ad is contributing to your bottom line.

3. Ignoring the sequence

It’s not just your multiple campaigns that impact the effectiveness of each ad. The multiple ads within a campaign impact each other. That’s why a consumer who’s seen your ad once might not respond to your message, but might convert after seeing the same message four times.

This means a lot for attribution. When you’re measuring ad effectiveness, you can’t just look at how the single adunit, or even the single message, performed. You need to understand how the message has followed consumers across their entire customer journey—from channel to channel, and within channels, all the way to the moment of conversion. Otherwise, you end up giving credit to an ad, when in fact the ad may only perform well across a specific sequence.You’re leaving critical information out of the picture.

To be sure, there a lot more ways that “last click” thinking persists. But you get the point: getting attribution right is a cross-channel, holistic task. Anything short is leaving data, and ultimately revenue, on the table.

Want to learn a bit more about the state of attribution today? Check out the latest Forrester report on cross-channel attribution providers.