Does The Number Of Links On A Page Affect Ranking?
by Jon Ricerca
http://www.SearchEngineGeek.com
Lots
of research has focused on inbound links to a site, but little
has focused on the number of links actually on a page (outbound
or to other parts of a site). Many SEO gurus have recently been
talking about something they call "PR Leak" which seems
to be a theory that the more outbound links you have, the more
your page rank on Google "leaks" away.
That concept isn't found in the academic papers published by the
founders of Google, but does seem to be accepted by a majority
of SEOs. I decided it was time to take a look at the number of
links present on a page and how that number correlates with ranking.
The
methodology: I gathered the results of the queries that were naturally
performed last month by myself and three associates using the
two leading search engines and analyzed them. I counted the number
of links on the page (references to "href") and tabulated
the results against the ranking of the URL in the search results.
The tabulated results were finally converted into a normalized
"ranking correlation." The results for each of the two
leading search engines were kept separate so that we could discover
any differences between the two leading search engines for this
factor.
The
resulting graphs show the results for groupings of number of links
normalized into a number between -100 and +100 showing the likelihood
of being ranked higher/lower. A value of +100 shows that all 10
rankings were in the proper order to show that pages of the studied
value ALWAYS rank HIGHER than pages of another value. A value
of -100 shows that all 10 rankings were in the proper order to
show that pages of the studied value ALWAYS rank LOWER than pages
of another value. Numbers in between show the varying likelihood
of rankings proportionally between - 100 and +100.
That
is the number you see on the Y-axis. On the X-axis, we have the
number of links found. They are grouped into sets of 10 in order
to increase the statistical significance with the amount of data
we had available to analyze. Here are the graphs for the two leading
search engines:
The number of links were grouped in this way in order to increase
the number of data points available. Unfortunately it also reduces
the precision of the results. One is able to see that 91-100 links
rank much higher than 1-10 links, but you are unable to see if
77 links rank differently than 79 links (for example).
The
result is very conclusive. Both leading search engines rank pages
with more links much higher than pages with fewer links!
Once
again, it appears that the SEOs touting the "PR Leak"
theory are simply wrong. If their theory held any weight at all,
we should see the exact opposite. Pages with more links should
rank lower on average.
Notes:
1.
There was no exercise to attempt to isolate different keywords.
I merely took a random sampling of the queries performed by myself
and three associates during the month.
2.
This is merely a correlation study, so it cannot be determined
from this study whether the leading search engines purposefully
entertain this factor or not. The actual factors used may be far
distant from the factor we studied.
Jon Ricerca is one of the leading researchers and
authors of the Search Engine Ranking Factor (SERF) reports at SearchEngineGeek.com.
For access to the other SERF reports, please visit: http://www.SearchEngineGeek.com
