A website devoted to analysing the political bias of 15 of NZ’s most viewed media websites is mediabias.co.nz which applies (to the extent that is possible with its methodology) an objective test on this.

Every day, we collect news articles from the most popular New Zealand political media sources, including the mainstream media and political blogs. The full text of each article is extracted with a content extraction algorithm and indexed with a full text search database for further filtering.

Once the articles for a given day are collected, we determine whether to analyse an article based on whether the article mentions a current member of parliament (MP) or political party (current on the day of publication). We maintain a database of all elected MPs and political parties.

How often a political party or its members in (or out of) parliament gets mentioned won’t itself a measure of bias as it’s rather hard to avoid stating which government minister is making an announcement, and by virtue of their being in power, more space/minutes is likely to be given to them than to opposition parties (including those affected by decisions), particularly when something is non-controversial. But if there is a major disparity in coverage of the government comments and those of opposition parties, then that is a good measure of bias.

This approach also doesn’t take into account attacks by the likes of Stuff on critics of government policies, or Tova O’Brien’s ‘gotcha’ politics, usually aimed at Judith Collins who she clearly doesn’t like.

To analyse the bias of each media source, for each filtered article, we analyse the sentiment of each sentence in the article and extract references to MPs and political parties (entities) from the text. The sentiment score of sentences that mention MPs or political parties, contribute towards the calculation of each media source’s bias.

The entity extraction and sentence sentiment analysis is performed with the Google Cloud Natural Language engine, which uses neural-network based entity extraction and sentiment analysis models.

That seems rather ethereal and not necessarily accurate, however, the actual results of the analysis seem pretty much in accord with what we know. Only theBFD and KiwiBlog have a right wing bias; interest.co.nz leans slightly to the left, the rest well to the left.