Of course I will not say who the client is, but I will alert them to this post and subsequently the article (and they may also not know about Clipmarks, so it is a win-win-win) I figured that recommending an article via blog post would be an interesting way to go about doing things.
For more info on this topic, click on the sphere button.
In analyzing the data, we found the most obvious change was a decline in the average order value (AOV) during the free shipping offer period. The magnitude of the decline varied, but there was a definite decline nonetheless. In January and March, the AOV declined by 2.2% and 3.1% respectively, while the decline in February was much larger at almost 20%. These AOV declines resulted in a concurrent decline in return on advertising spend (ROAS), a key performance metric for this campaign, during each of the offer periods. The decline in ROAS ranged from 30-70% during the free shipping periods, indicating a clear loss of efficiency during the promotional cycles.