Sherwin's previous job was director-general of the Ministry of Agriculture and Forestry and before that deputy governor of the Reserve Bank.
His fellow commissioners are Sally Davenport, professor of management at Victoria University, and Graham Scott, best known as the secretary to the Treasury during the days of radical economic reform in the mid-1980s and early 1990s.
Despite adopting the policy prescriptions internationally favoured at that time, New Zealand's economy has continued to underperform its erstwhile peers, to the point that average incomes are around 30 per cent and 50 per cent lower than Australians' and Americans' respectively.
Sherwin is wary of admitting to any preconceptions about why New Zealand productivity levels are so low and what has been holding it back.
"I have some thoughts and ideas about what matters, but it is important that those get subject to test and there are two other commissioners who have different perspectives," he said.
"Some things are pretty obvious. We are a very small economy. I think that matters. We have a persistent tension between having firms that are big enough to be credible on the international stage, while preserving competition domestically. Fonterra is obviously the extreme case of that."
It is significant that New Zealand is a long way from other markets, and our lack of savings matters too, he said.
The commission has to prove it can add value to public policy.
"I think the added value comes from being dedicated to a focus on productivity and from being independent and therefore a step removed from the political process and able to be more forthright," he said.
"Government departments can't do that on their own. We will also have longer than most government departments would to undertake our work."
But in the end the value added by the commission would depend on the quality of its analysis and of the evidence and information it musters.
Crucial to the process will be engagement with interested parties. There would typically be two rounds of public submissions in the course of an inquiry, first in response to an initial paper setting out the commission's view of what the issues are and later to its draft recommendations.
"People will have plenty of opportunity to engage and tell us where they think we are wrong or have our heads in the clouds."
In this context being a small country with short lines of communication may help - what Helen Clark called the "intimate democracy".
The flipside is that conflicts of interest are more likely to arise when the commission looks to supplement its own staff with contracts to think-tanks or law firms with expertise relevant to a particular inquiry.
"The sorts of people we might want to contract to do a piece of work might also be sought after by interest groups wanting to advise them or write their submission or whatever. We need to be able to manage that quite carefully."
The Productivity Commission has a staff of 15, compared with more than 200 in Australia, and in these days of fiscal austerity its funding of $5 million has been carved out of existing departmental budgets.
Sherwin says he is very happy with the calibre of people it has attracted.
The commission is trying to make a positive difference to the country's productivity record. That would take years and it would never really know how much it had influenced.
But Sherwin has no doubt it is worth the effort.
