In all areas of life, to test whether an action is effective, we need to have an idea of what would have happened in the absence of that action. In science, controlled experiments are done to show what works and what doesn't work. In the absence of such experiments, we simply opine.
In social sciences and in politics, we cannot do controlled experiments, so we really do not know anything for sure. Rather, certain beliefs can be shown to be more likely to be true, other beliefs less likely, and some beliefs are so implausible to be practically impossible.
To show that an action is likely to have been effective, you have to be able to argue convincingly that a different outcome would have occurred had the action not taken place. Thus the logical principles of argument are very important in establishing likely truths.
In economic history this is obviously very important. To establish whether the 1989 Reserve Bank Act made any difference to subsequent inflation we have to be able to argue that inflation rates in New Zealand would otherwise have been higher.
By looking at what happened in the 1990s in other countries, we can argue that New Zealand inflation rates probably were little affected by the introduction of inflation targeting in 1989.
In politics, the Maori Party has been in a state of descent since 2011; a popularity decline most recently revealed in the Ikaroa-Rawhiti byelection. The commonly held assumption, by journalists and apparently by Maori voters, has been that this decline has been due to the Maori Party's participation in the National-led Government. If we can establish - or at least convincingly argue - that the Maori Party would have been thriving today had it not been for that fateful 2008 decision, then we can claim that "getting into bed with National" has been the principal cause of this decline.
A further question has been the effectiveness of the Maori Party. Has its participation in government made a difference to societal outcomes beneficial to Maori?
The Maori Party had to make choices based on the cards that were dealt to it in the 2008 and 2011 elections. National and Act wanted to abolish the Maori electorates. In 2008, National and Act gained enough seats to govern without the participation of other parties. So, we can argue that the retention of the Maori seats was the first tangible outcome of the choice to participate in government. Indeed the threat of abolition of the Maori seats meant that Tariana Turia and Pita Sharples had little choice but to join the Key Government.
The election result was little different in 2011. Once again, John Key had the numbers to form a government without the participation of the Maori Party. Their option was to join and make some difference, or to not join and make no difference.
Other policy outcomes that the Maori Party pushed for - outcomes favourable to Maori - include the repeal of Labour's Foreshore and Seabed Act, the infusion of Whanau Ora into the welfare mix, and increased cigarette taxes. Had the Maori Party been in opposition, these policy outcomes would not have taken place.
So why is the Maori Party so unpopular? Clearly its internal dynamics are now dysfunctional. But this dysfunction can easily be seen as a result of the schism of 2011, not its cause. That schism itself was caused by the misplaced belief of Hone Harawira that the Maori Party had been ineffective.
The problem would appear to be largely one of perception; perception that was amplified by those who had not adequately appreciated the substantial achievements of the Maori Party.
The logic is irrefutable. The Maori Party has made a positive difference to Maori, compared to what might otherwise have happened.
Keith Rankin teaches economics at Unitec Institute of Technology.