# Very easy question

#### Italy89

##### New Member
Hey guys,

This is a pretty easy question, probably this is not even the right category, still I will give it a try

Let me just say that many years have passed since I took data analysis and statistic at Uni, so forgive me, especially because my question is not strictly related but...

So, I have 3K sellers and they all started their activity on different dates, starting from September 2019. I want to create a chart to evaluate their performances over a period of 6 months, but I do want to take their "starting date" into consideration, so I need to find a way to connect how much they have sold and for how long, then to rate them based on numbers that make sense.

So:
- I can divide

(number of products sold)/(days of activation)

given that the products cost the same. In this case I don't really take into consideration their "longevity" though, so I can have two stores with the same results but one has been active for 6 months, the other for 20 days.

Ex:
A: sold (200 units), days since act (100)-> AVG/day= 2
B: sold (10 units), days since act (5)-> AVG/day=2

- I can multiply these results for 182 (days in 6 months, the period I am taking into consideration), but again: not ok, it is a projection. I am not sure if they will actually sell that amount.

So my question is: how would you create the chart? How would you normalize those numbers to discriminate longevity and have a final number that makes sense!?

Sorry for my English, not a native and excuse me for the question: I don't now if I am rusty in math (I have a degree in analitical chemistry, but.... Ahah) or it's the quarantine hysteria.

Thanks!

#### Karabiner

##### TS Contributor
Why six months, if so many subjects could not reach this by far?

Would stratification be an option? I.e. to create 3 or more subgroups, based on starting date, and compare within groups?

With kind regards

Karabiner

#### Italy89

##### New Member
Unfortunately stratification is not an option, since i am talking about 3k stores, all of them starting on different dates.

I know, it doesn't really make sense, but this is one of the charts I need to create...the monthly analysis will be way easier.