Proper optimization requires correct reporting. Correct reporting requires timezone alignment across all systems. This makes sense, if your numbers are wrong, you’re optimizing for the wrong thing.
How bad is the problem?
It depends where you live and what systems you work with. A common formula used in optimization is the calculation of rCPM:
1000 * Revenue * (Filled Impressions / Server Impressions)
Suppose that your server is running on EST and that the advertiser’s reports use GMT. A single day report will be off by five hours! That’s over 20% of the day.
But is it really that bad?
Not quite. Things are less grim for two reasons:
First, even though the reports are misaligned, each will contain data from previous days. Those 5 hours aren’t necessarily zeroes, they’re just taken from the wrong day. Instead of 12AM – 5AM, you’re getting 5PM – 12PM from the previous day. Still very wrong, but maybe not disastrously wrong.
Second, you’re probably not running daily reports. If you report over a longer time period, there’s more data and the problem is largely mitigated. 5 hours, is over 20% of a single day. However, it’s only 3% of a week and less than 1% of a month.
What to do?
Many reporting systems do allow you specify your timezone. Do it whenever possible!
If that doesn’t work, you can try reaching out to the advertiser. They might be able to change the timezone for you.
If you can use longer date ranges, that will help.
Another option is to use a 5-day rolling average. This has the advantage of smoothing out your data and also mitigates the date range problem.
Finally, if everything else fails, you can align all your reporting around the system you can’t change. If you have 5 systems that let you specify a timezone and 1 system that doesn’t. You can change the 5 to use the same timezone as the 1. As long as the timezone is reasonable, this can work fairly well. If you’re stuck with multiple systems you can’t change, try to align the most important ones.