Domain Authority 30

Previously, Page Rank was the more appropriate ranking system for how well a page or domain ranks on Google. However, Google has since temporarily (or permanently?) discontinued Page Rank.

Hence, now the closest measure to Page Rank is Domain Authority, by the company Moz.

Currently, Mathtuition88 has Domain Authority 30. Domain Authority is on a logarithmic scale, meaning that it is harder to increase from 80 to 90 than from 30 to 40.

According to the Moz forum, the Head Data Scientist said that a formula to convert to linear scale from the logarithm scale is:

If you just want an estimate, take the log (base 10). You’ll get a value from zero to two that will be roughly linear, and then you can scale it up to whatever range you need.

To be specific, a formula to convert Moz scale to “normal non-logarithmic scale” out of 100 is:

New Score = log(DA) * 50

Using this formula, the score for Mathtuition88 is log(30)*50 = 73.9.

Actually, I am a little skeptical about the above formula and how accurate it is. For instance, I think that one should take exponential (to the correct base) instead of log again for the “non-logarithmic” scale?

For instance,

log(40)* 50 = 80.1

log(80)*50 = 95.2

log(90)*50 = 97.7

Hence, to increase from DA 30 to DA 40 corresponds to an increase in “New Score” of 6.2. To increase from DA 80 to DA 90 corresponds to an increase in “New Score” of 2.5. This does not tally with the idea of “it is harder to increase from 80 to 90 than from 30 to 40”.

Another quote from Moz:

Dr. Matt Peters, Moz’s head of Data Science:

“PA and DA are the output from a machine learning model that we then rescale to values between 1-100.  The raw output from the model is dimensionless and doesn’t have any interesting meaning.  The rescaling is linear, but the inputs to the model are rescaled logarithmically before being used in the model.  We use the natural log (base e) but the base is pretty arbitrary since one can transform from one base to another by changing coefficients, and the coefficients themselves are set in a regression.  The key point is that since the inputs have a log applied to them it is much harder to increase DA from say 70 to 80 then it is from 30 to 40.”

Based on this, another formula to convert Moz’s Domain Authority to a Non-logarithmic score could be:

New Score = [e^(DA)/e^100)] * (100)?

The problem with the above formula is that it gives very low scores close to 0.

Mathtuition88’s Domain Authority:

MOZDomain Authority30


Author: mathtuition88

Math and Education Blog

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