I have a table of sales growth rates by month calculated thus:

$$\text{growth rate}_i=\dfrac{\text{sales in month } i-\text{sales in January}}{\text{sales in January}}$$

What should I call this table? The best I've come up with it "sales growth rates from January by month". Is this ambiguous? Is there a technical term for this?

(I've had almost nothing to do in my life with anything that counts money or statistics for that matter).

  • 3
    $\begingroup$ Percentage change in sales between January and month $i$. $\endgroup$ Apr 8 '14 at 18:36

Some suggestions, besides Alecos':

  • Relative sales growth;
  • Sales growth ratio between month j and January;

I believe you have a ratio rather than a rate. A ratio has the same measurement unit in numerator and denominator, and a rate does not.

Here are some videos with more insights on this subject.

Consider the following example:

enter image description here

At the column D we have a ratio, similar from what you are doing:

$$\text{Sales growth on month} \hspace{1mm} j = [(\frac{Sales_j}{Sales_{January}}) -1] \times 100$$

So, sales in February increased 25% in relation to January. Sales on March decreased -3% in comparison with the sales from January, and so on.

At column E we have a rate: sales growth by month (which means we have different units on the numerator and the denominator).

We get the values on column E according to the following equation:

$$\text{Sales}\hspace{1mm} \text{on} \hspace{1mm} \text{month} \hspace{1mm} j = \text{Sales}\hspace{1mm} \text{on} \hspace{1mm} \text{January} \times (1 + i)^t$$


t = time in months.
i = sales growth by month.

So in this second example one would have an increase on sales of 25% by month on February, a decrease of -1.3% by month on March, and so on.


First of all, this is not a growth rate. The reason is that the rate is always attached to a time period, e.g. annual or monthly rate. If you fixed $i$, then you could still call your metric a rate assuming that implicitly it's for $i$ months. Since, your $i$ appears to be variable, this is not the growth rate but it's a growth.

You could call your metric percentage change as others suggested, but if you wanted to be more specific you could add a qualifier simple, as opposed to continuously compounded which would have been $\ln(\frac{s_i}{s_J})$

UPDATE: if your $i$ is from a standard interval set such as a month, quarter, year, then you can add month-to-month or quarter-over-quarter qualifier.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.