Week-on-Week (or WoW) means comparing data from one week to the previous week. For example, you could say “We had revenue growth of 2% Week-on-Week” which would mean that last week had 2% more revenue than the previous week.
When comparing Week-on-Week, this can mean comparing any 7 day period to the previous 7 days. Or similarly, comparing any metric to the same time frame 7 days before it (eg 2 pm – 4 pm on Monday compared to 2 pm – 4 pm the week before).
Some platforms default to a week as Monday-Sunday, some use Sunday-Saturday. If you are comparing across platforms, you should make sure they both use the same timeframe.
It is useful to compare short term trends using WoW calculations. For longer-term trends, you should use Month-on-Month, Quarter-on-Quarter, or Year-on-Year.
This is how you calculate the change in metrics from one week to the next.
Week-on-Week Change =
((Any Metric ÷ Same Metric from previous week) -1) x100
To calculate your Week-on-Week you can’t just divide this week’s results by the previous week’s results. You need to subtract 1 after dividing your metric by the previous week.
This is so you can see how much performance has changed, as opposed to how it relates to the previous week.
This can be difficult to understand, so let’s look at an example:
This week you made 2 sales. Last week you made 1 sale.
With metric ÷ the previous week you get 2 ÷ 1 = 2. If you turn this into a percentage it would be 200%. You can then say: “This week’s sales were at 200% the level of last week”.
If instead, you use ((Any Metric ÷ Same Metric from previous week) -1) you get (2 ÷ 1) -1 = 1. You can then say “This week saw 100% more sales than last week”. Or similarly “We had a 100% increase in sales compared to last week”. Or even “Sales went up by 100% this week”.
The second version is what is used as standard simply because it’s easier to understand and to use conversationally.