Has MicroData ISBN returns 1 when RankGear finds the Microdata attribute itemprop="isbn" in a page’s rendered body HTML, and 0 when it does not. It is a literal text match on the markup, not a check that the ISBN is valid or that the surrounding Microdata item is correctly built.
| Factor ID | RG-SCM-022 |
|---|---|
| Family | Structured Data — Microdata |
| Measurement | Binary presence (0 / 1) |
| Measured zone | Rendered body HTML with scripts removed |
What it measures
This factor reports whether RankGear finds the Microdata attribute itemprop="isbn" in the rendered body after script elements are removed. It is a single yes/no signal about the presence of a book-identifier property in the page markup, not a measure of how many books are marked up or how accurate the identifiers are.
How RankGear measures it
RankGear performs a case-insensitive search for the literal double-quoted form itemprop="isbn". It returns 1 when at least one match exists in the rendered body and 0 otherwise. The match is on the exact character sequence — the attribute name, equals sign, opening double quote, and property value must be contiguous.
What RankGear looks for
<span itemprop="isbn">978-0-13-468599-1</span>| Value | Meaning |
|---|---|
| 1 | At least one itemprop="isbn" attribute is present in the rendered body HTML. |
| 0 | No matching attribute was found (or it uses single quotes or extra spacing, which do not match). |
How to optimize it
Treat this as an observation about your markup rather than a target to chase. If your page describes a book or edition, add itemprop="isbn" only as part of the valid ISBN assigned to that book, and keep the value aligned with the visible content and the vocabulary expected by its parent item type. Do not add the attribute to pages that are not about a specific book or edition — a present-but-meaningless ISBN helps no one, and the factor cannot tell you whether the identifier is genuinely correct.
Important considerations
- The detector pattern-matches HTML text instead of parsing or validating a Microdata item graph, so a 1 confirms the string is present, not that the item is well-formed.
- It requires the attribute name, equals sign, double quotes, and property value to be contiguous; single quotes or added spacing do not match.
- Scripts are removed before matching, and capitalization does not affect detection.
- Validate the parent item type, property value, nesting, and structured-data eligibility independently — this factor does not do that for you.
- Presence of this attribute correlates with pages in a measured result set; it does not by itself cause or guarantee a ranking. Read it as one prioritization signal among many, not as a lever that moves position on its own.
Related factors
Part of the Factors reference · how RankGear measures · glossary.