## Five Times Lower / Less / Smaller

How can something be five times lower, or five times less, or five times smaller than something else?

Clearly, the people who write such expressions do not understand fractions, decimals, or percentages (although they might comprehend factors or orders of magnitude). Petroleum engineers, however, should exhibit ample evidence in their writing that they eat fractions, decimals, and percentages for breakfast. Therefore, they should never use these expressions, lest someone think the other numbers in the document equally fuzzy.

In the engineering world, five times larger means 5× or “multiply by 5.” If X is smaller than Y by a factor of five, then X = Y/5. That means X is one-fifth the size of Y, or 20% of the size, which translates to 80% smaller or a value that is 80% lower. Use those expressions instead to ensure clarity and give the impression that your number sense is 100%.

### 3 Responses to “Five Times Lower / Less / Smaller”

1. Jim Norwood Says:

I think that you and I are apparently among the few that feel this way, but I agree with you wholeheartedly.

I even heard Neil deGrasse Tyson on this week’s Cosmos say something to the effect that we would have to be a million times smaller to operate within some atomic realm.

To me, 1x smaller is zero, and you can’t get much smaller than that!

2. Kay Latona Says:

I couldn’t agree more! I have too often wondered what I was missing when I heard or read “X times smaller …”

3. Brendan Says:

This bugs me every time I hear it.