Backlink Sampling

SE ANALYST uses link sampling to determine Backlink quality and calculated PageRank.  This section records the integrity of the sample set and other significant sampling metrics.

Field		Dataline Description
Backlink Sampling	link:	Link: query of URL stripped to domain level (home page); excluding internal links.  Specific engine queries as follows: Alltheweb*: Link:http://www.domain.com MSN: Link:http://www.domain.com *Alltheweb is a proxy for Yahoo
	Site:	Site: query of URL stripped to domain level (home page).  Results are from the Top Page engine.
	TpLp	Backlinks reported by Backlink Search Engine.  Choices are Yahoo or MSN; excluding internal links.  Specific engine queries as follows: Yahoo / Alltheweb*: Link:http://www.domain.com –site:domain.com MSN: Link:http://www.domain.com –site:domain.com *Alltheweb is a proxy for Yahoo The “-site:domain.com” portion of the query includes the complete authority name which may include a sub-domain. Examples: URL (Uniform Resource Locator) Authority http://www.seanalyst.com seanalyst.com http://christmas.allrecipes.com/ christmas.allrecipes.com
	TpLp Sample	Number of sample Backlinks attained for analysis from TpLp; excluding internal links.
	TpLp Dead	Number of sample Backlinks found to be either dead pages or missing links to Top Page URL.  Note that links must be an exact URL match to the top page URL.  Even small differences such as a missing “www” or the inclusion of “…index.htm” will not be counted. Dead links are considered normal attrition of a steady state condition.  Therefore, it may be assumed that there are as many new links that have not been reported as dead links found.  In this regard, dead links are not used to diminish the pro-rated calculated number of links in each of the filters or calculated PR.
	CI 95%?	% confidence interval based on number of samples attained and reported link universe (Link: query for Top Page).
	Calc PR	Calculated PR base on sample backlinks attained using the following formula: PR(a) = (1-d) + d(PR(t1)/C(t1) + ... + PR(tn)/C(tn))    Where:      't1 - tn' are pages linking to ‘A’      'C' is the number of outbound links on that page      'd' is a damping factor, typically set to 0.85. Google toolbar reported PR values are first converted from log values [exponentiation: PRexp=PRtool^LogBase] for calculation purposes and then converted back to log values [PRtool=LogLogBase (PRexp)] for reporting purposes. Example: Assuming page A has three (3) backlinks ; ‘d’ = .85; and log base is 10, then: Link PR (toolbar) Outbound links PRtool^LogBase /outbound links 1st link 5 75 1,333.3 2nd link 4 10 1000.0 3rd link 2 15 6.7 subtotal 2,340.0 d value x.85 1989.0 (10^.15) +(1-d)=.15 1.413 PR in log form total 1990.413 Convert from log form Public PR 2.804