Should you set a long-term cookie for affiliate tracking?
If I had a penny for every advertiser that asked, “Should we reduce our cookie duration?” I would have an awful lot of pennies by now.
I love getting this question, as it’s an easy one to answer and it almost never fails. The answer is almost always a definitive “NO.”
Why, you may ask? Outside of considered purchases with longer buying cycles, cookie length tends to be one of those attributes that creates more of a perceived value to affiliates rather than a real cost to advertisers.
What we’ve found, on average, is that anywhere between 80-95% of affiliate sales occur within 24 hours of the last click. So, in reality, changing the cookie duration has minimal effect on attribution through the channel. The channel is built on relationship management, and it is in an advertiser’s best interest to keep publisher partners happy – provided that’s not to the detriment of the advertiser.
The cookie duration is one of the cases in which one might think it impacts attribution and that shortening the window will save cost, but historical evidence across many verticals has identified that this change increases the risk of rocking the boat with publisher partners at a much greater rate than it benefits the bottom line.
A simple analysis, using affiliate network click data vs. conversion data, can help isolate cookie impact and proves this phenomenon. We’ve performed this analysis many times, with similar results across varied retail verticals.
Here’s an example of this analysis in a nice visual line graph. This was generated by taking a sample of the past 30 days of sales for a particular program:
This chart represents a (non-considered purchase) program that has the industry standard, 45-day cookie. Notice the steep drop-off of order count after just 2 days. In this example, 94% of all orders occurred within one day and 95% occurred within two days.
Having an extended cookie duration is a great tool that creates a perceived value for the program. It gives publishers confidence that we value their traffic and want to give them as much opportunity to earn commissions as possible while, at the same time, not materially changing our cost or attribution for the channel.