As I’ve discussed in a previous blog post, a dashboard that doesn’t visually flag metrics that require attention will likely flop with users. In fact, the lack of such indicators could be the number one reason why so many dashboards fail to deliver acceptable levels of user satisfaction and traction.

While not as common on dashboards as other flagging methods, participants in my Practical Dashboards workshops often ask about “% deviation from trailing average”, so I’ve written this post to illustrate why that method actually isn’t much better than the more common alternatives.