Consistency is highly valued by the public. Lack of consistency will lead to a loss of trust in a brand, whether in public or private sector. Especially in sales, a change to a menu or recipe (New Coke anyone?) almost always leads to a loss of customers, unless accompanied by a massive promotional campaign to sell the change as an upgrade - and sometimes not even then. One of the reasons a certain global burger chain is so successful is the sameness - the consistency - of its product, across all times and locations. Taste and nutrition are secondary considerations.

Rule changes are a great way to discourage citizens from making use of a government program. We are seeing evidence of that with the vaccine rollout.

When the program first began, access to vaccination was based on categories that gave priority to the elderly and people in pandemic response roles. The reasoning was explained, and the priority listing had a high level of public acceptance.

Since then, however, the rules changed several times in relation to who was eligible to receive what vaccine. In April this year the government ruled that only the Pfizer vaccine would be available to people under the age of 50. Anyone over 50 would be ineligible to receive Pfizer, and could only receive the alternative, AstraZeneca. At issue was the risk that the AstraZeneca vaccine might cause dangerous blood clots for some. Then the age limit changed again, to 60, based on a recommendation from the Australian Technical Group on Immunisation on June 17. The rules changed yet again when in an evening press conference last week the Prime Minister announced anyone under 40 could have access to AstraZeneca after talking with their doctor.

Any policy adviser familiar with the bus timetable problem would have predicted that this would lead to a sharp and swift drop in vaccinations. That is exactly what happened with the second rule change. Doctors reported hundreds of cancellations of appointments; vaccination numbers fell across the country.

The recent outbreak that began in NSW is bringing the rates back up again. The obvious danger posed by a new outbreak is a powerful incentive to vaccinate. Nevertheless, the starting number of people to be vaccinated would have been higher had it not been for the rule change.

The effect of the most recent rule change is harder to assess, as it is accompanied by outbreaks and lockdowns around the country. Most observers however consider it has added to confusion.

The technical advice was undoubtedly well considered and based on emerging evidence. The great strength of governments' (Commonwealth, state and territory) responses to the pandemic has been that they have been based on expert advice. It is necessary and valuable. The big question though is whether technical medical advice on its own is enough to ensure the vaccination program works well.

There is a misguided debate in public administration circles over whether the public service should employ specialists or generalists. It's like an argument over whether a sailing boat needs a hull or mast. The ship of state needs both technical expertise and broad perspectives.

Specialists sometimes deride generalists as having no skills or expertise. That is a mistake. Generalist policy skills are developed through exposure to a wide variety of problems and concerns, and are no less a skill for being general. Indeed, the Australian Public Service at one time had a program where selected graduate employees were rotated between departments and agencies precisely to expose them to different environments and issues.

From a broader public policy perspective there are three problems with an age cut-off for access to the Pfizer vaccine. The first is the messaging. When changes are made based on different evidence it affects confidence. While perfectly reasonable from a science perspective - new data frequently changes findings - from a policy perspective it put at risk public acceptance of the AstraZeneca vaccine.

The second is having a cut-off based on age. This goes against the deeply held Australian attachment to fairness in government policies. While some programs have age cut-offs (the age pension is an obvious example), for this to be acceptable it needs to be based on considerations of equity and have a well-defined rationale.

The third was the mandatory nature of the cut-off. If advice had been put out there to allow people to make their own decisions - that is, informed consent - it would have had a far greater level of acceptance. This would also have been a more familiar and acceptable way of dealing with changed evidence: people know that as new information comes to light the parameters around informed consent change.

Explaining it in simplistic analogies about how low the risk was did not cut through. Low risk/high consequence events influence public behaviours in all sorts of fields - driving, buying a lottery ticket, a person's decision to not break the law. There are lessons to be drawn from these areas that indicate that even though the blood clots are low risk, if people assess their risk of acquiring COVID-19 as lower - whether or not their assessment is accurate - they will be reluctant to take the AstraZeneca vaccine. This is also why rates will increase if there are more outbreaks - people will assess their Covid risk as higher.

It is hard to avoid a conclusion that the main driver for making it the only vaccine available for over 50s was that supplies of the AstraZeneca vaccine were plentiful and the Pfizer vaccine was and is in short supply. Health Minister Greg Hunt implicitly confirmed this when he suggested that people concerned about AstraZeneca should wait until later in the year when other vaccines would become more widely available - a position he has since revised.

This is not arguing that technical advice should not be the main input into decisions about the vaccine. It should remain the primary consideration - but with a leavening of broader perspectives that may help avoid the missteps we have seen to date.

Vaccine advice, it appears, is going directly to ministers without mediation; it lacks the layering of broad consideration that generally applies to policy.

If for example decisions on vaccine access were considered through cabinet submissions, the excellent institution of coordination comments would allow other departments to express opinions. Coordination comments may not often change policy outcomes, but they do give ministers food for thought and foster wide ranging discussions.

The lack of policy breadth is also in part due to the hollowing out of policy expertise in the public service. It used to be that in a time of crisis a government could convene a group of senior people from different departments to look at policies from diverse viewpoints. The type of conversation that follows ("that reminds me of when we - implemented the GST/established the fisheries authority/revised social security ... etc.") draws out lessons and parallels. This is now rare. Instead, large multinational consulting firms are called on - who, although they might have smart people, do not have that history of public policy implementation.

Often ministers and their offices are happy to receive technical or specialist advice directly, without a mediating layer, because they think public policy is the same as politics (where they already have expertise). That is mistaken. Thinking through both intended and unintended consequences and developing policy advice based on depth of experience with comparable situations is not the same as devising a political message.

Broader advice from experienced public policy professionals might not have changed how the government went ahead on vaccines; but if nothing else, it would have changed its public presentation. As we continue to struggle with the pandemic, the governments would be well advised to complement technical advice with a sprinkling of good generalists who can give them fresh insights.