This morning I logged into Google Analytics and found that there was a new feature on the dashboard - weekly and monthly graphing.

On sites that have the typical business week roller coaster appearance when you look at a lot of data, say over a year, it can be difficult to see trends. For example here’s a busy e-commerce site:

You can generally get a feel for what’s going on in that graph, but it’s much clearer in the graph below which has one data point for each week. (It looks like there were some problems in December)…

Yes, you lose some detail, but when looking at a lot of data you’re able to better see the forest rather than the trees. The roller coaster trends you see in analytics tend to be weekly trends with traffic high during the work week and low on the weekend. So a weekly graph smooths out those normal ups and downs and lets you see very clearly how you did on a particular week.

When you get to monthly summary graphs the trends aren’t quite as detailed…

I suppose that is useful for businesses who think in terms of performance month-to-month, but thinking that way will hide downturns that are spread over two months and exaggerate ones that are contained completely within a single month. In other words, unlike the weekly graph, it’s not smoothing out routine variations - it’s just removing details (that may be important).

The weekly and monthly graphs are useful even on sites which don’t see routine weekly variation. Here are the graphs from a blog site that has pretty consistent traffic (weekends are about the same as weekdays). We start with the standard daily graph…

That’s a much smoother graph than its counter part from the e-commerce site above (the first graph), but this next graph (the weekly graph) makes the trends very clear without losing much detail…

Even though you can see the trends in the daily graph, that weekly graph really does a much better job of smoothing the line out and showing the general trend, though it does hide the very last spike in traffic.

The monthly graph however, once again smooths things out so much that it loses important details…

According to that graph the growth rate of the site is nearly exponential. It loses the recent spikes and makes thing seem a little too optimistic. The accurate message from the data should be “growth is good, but if spikes in traffic aren’t maintained traffic may go down somewhat”. The monthly graph makes it seem like growth into the future is unlimited.

Theh bottom line is that Google has added another useful tool, but as with all statistical tools you need to be careful that the conclusions drawn from these tools don’t hide important trends in the data. In this particular case I believe the weekly graphs are a huge asset, but the monthly graphs aggregate too much data to accurately describe the underlying trends. Of course, as you get years worth of data accumulated, the monthly graphs will be more appropriate to show long-term tending.

Tags: graphing
Categories: Google Analytics, Web Analytics