Standard deviation measures how widely a set of observed values is spread around their mean. A small value means the numbers cluster tightly near the average; a large value means they scatter. RankGear’s deficit calculations use the sample standard deviation.
| Term | Standard Deviation |
|---|---|
| Category | Statistics and Evidence |
| Also known as | STDEV, Sample Standard Deviation |
| Where it appears | Deficit strategies and statistics |
What it means in RankGear
When RankGear compares your page against the top-ranking competitors for a keyword, it does not just look at the average competitor value for a factor. It also asks how much those competitors disagree with each other. Standard deviation is the number that captures that disagreement. It feeds the deficit strategies and statistics, where the spread of competitor values decides how far your page can drift from the mean before it stands out as an outlier. A factor where the top pages all land near the same word count carries a small standard deviation; one where they range from terse to sprawling carries a large one.
How to interpret it
Read standard deviation alongside the mean, never on its own. The mean tells you the target; the standard deviation tells you how much room there is around that target. A tight spread means the leaders converged on a narrow range and a deficit against them is worth closing precisely. A wide spread means the leaders themselves disagree, so the same factor is a weaker signal and an exact match matters less. It is expressed in the same units as the underlying factor, so a standard deviation of 300 words is read against a mean measured in words, not as a percentage.
| Spread | What it tells you |
|---|---|
| Small standard deviation | Top pages agree closely; the target range is narrow and the factor is a firmer signal. |
| Large standard deviation | Top pages vary widely; the target is loose and the factor discriminates less between winners. |
| Near zero | Confirm it is genuinely uniform rather than a missing or single-sample measurement. |
Example
Suppose two keywords both show a competitor mean of 1,200 words for on-page content. For the first, the standard deviation is 90 words: every top page sits between roughly 1,020 and 1,380 words, so a page at 700 words has a clear, actionable deficit. For the second, the standard deviation is 650 words: the leaders run from short landing pages to long guides, so the same 700-word page is well within the pack and the word-count deficit means far less. Same average, different spread, different call.
Important considerations
- A high or low standard deviation describes how competitors differ; it is not a score Google assigns and does not, on its own, say a page will rank.
- Standard deviation is only as trustworthy as the sample behind it. Small SERP samples make the spread unstable, so treat wide swings from a handful of results with caution.
- The value is in the factor’s own units, so compare spreads within a factor, not across factors with different scales.
- Check whether a near-zero result reflects true agreement among the top pages or simply a factor that was measured for only one of them.
Related terms
Part of the RankGear glossary · how RankGear measures · the 870 factors.