Question

Unfortunately the specification does not tell anything about precision.
The xml scheme definition states that it is of the type xsd:decimal:

<xsd:restriction base="xsd:decimal"> 
  <xsd:minInclusive value="0.0"/> 
  <xsd:maxInclusive value="1.0"/> 
</xsd:restriction> 

I have a sitemap generator that uses up to 10 positions after decimal point.
Where often only the last few positions differ. These numbers are perfectly right according to the xsd, but yet i found some pages(3,4) that state that only 0.0, 0.1, 0.2, .., 1.0 are valid values.

How will the search engines react to such a sitemap? Will some just round the value?

I know that it is unlikely that someone can provide an answer to that question, unless he works for that search engine, but i think experiences will also do.

Answer 1

I can’t speak for the precision of those values as I’ve never used anything other than a single decimal place.

In my experience though it doesn’t make much of a difference at all except that Google will try to crawl your higher priority pages first before the lower priority ones, and sometimes more frequently.

Unless you have thousands of pages on your site though, it really doesn’t make any difference.