Is 'biasedness' a real word?

Based upon my inability to find it in a dictionary, I would say no. Biasedness is not a word.

Biased: containing bias or showing prejudice does not really lend itself to a modification by degrees using the suffix -ness.

Rather, you would modify by comparison saying: more biased or less biased.

His opinion seemed more biased than that of his opponent.

Or, better yet, just use the word bias.

On review, the bias of the test was quite apparent.

Bias in this context will carry the same meaning as biasedness is trying to impart.

As there is the noun bias meaning an attitude based on prejudice there is actually no need for a word formation such as biasedness. Obviously the latter is a word some people use in spoken colloquial language that up to now has not obtained official status by dictionary makers.

But it is interesting to think about the logic of this new word formation. Often people have more sense than dictionary makers and what today is seen as incorrect may be common in the next or in two generations.

Well, what may be the cause for the new word? The noun bias is actually a foreign and exotic word and it is a metapher. It is used in the sense of prejudice, but actually means obliqueness. I might guess that people use this noun not so often as the word biased for prejudiced. And it is not so illogical when people form from the more common word biased a new noun "biasedness" that expresses clearly by its suffix the idea of "the state of being biased".

To my understanding the implied meaning of 'BIASEDNESS' OR 'BIASM' (neither word exists in the English language and as an aside I note that is it is good that the overall language specification is accurate) as opposed to 'BIAS' is notably a NEGATIVE versus a NEUTRAL one, and these are therefore not the same or suitable substitutes for each other. The former two - 'biasedness' or 'biasm' - imply a meaning of unfair tendency whereas the latter - 'bias' - a neutral tendency in general. Unfortunately, the English language does not seem to cater for this need or gap as a noun in the language for the negative version (only in the form or context of the adjective, namely 'biased') and in order to improvise or fill this gap for a noun one could say 'being biased' (or similarly use the verb of your specific context). For example, '..is a case of your abuse of power and biasedness' would in my mind be more elegant than the improvisation of the noun or adoption of the adjective by saying '..is a case of of your abuse of power and being biased'. It would thus appear to me that there is a genuine gap in the English language which would warrant the introduction of such a word.

I believe that the word 'lol' (meaning 'lots of laughter') was introduced as a new English word by the Oxford dictionary. I presume the reason was due to the word 'lol' being used so extensively and consistently over years, however, the use of the word 'biasedness' is in a sense not so acute (used at a lesser rate or lesser quantity over the same period), yet the sought 'need' for it has surely existed over a much longer period (more historically, with the internet making us more aware of it) which would warrant its introduction much the same, well, in my opinion and reasoned estimation.