Death and taxes are certainties. After more than 30 years of professional life, I have learned that there are a few more items on the definites list.

I know now that, in fact, the world is full of certainties beyond death and taxes. Our lives are fundamentally predictable. Business is business, people are people, trains are often crowded, and coffee is a requirement. Accident and novelty notwithstanding, I can be pretty sure what tomorrow will bring.

This is not to say that I readily accept this reality. I am much more inclined to fear the future as something entirely unpredictable and out of control. It seems that my biology requires risk, perhaps to keep me on my toes and on the lookout for lions and the snake in the grass.

My good fortune is that my chosen profession is founded on evidence, the raw material to understand, mitigate and avoid risk. I am trained to find as much certainty as is humanly possible and then to apply that certainty to first reduce risk and ultimately help alleviate fear.

A noble profession you would think.

At some level, I like to think so. Gathering evidence to inform decision making seems like a calming exercise that should benefit the many. Thinking, researching and evaluating my way through environmental problems should be a good thing to do in a world where resources are finite and demand voracious.

Science, the gathering and evaluation of evidence, surely is our best source of certainty. It bounds events through understanding and generates evidence that makes life predictable.

Imagine my shock when in an article from the Alliance for Useful Evidence I came across this quote from a senior UK policymaker…

One insider’s view of policymakers’ hierarchy of evidence
1. Expert evidence (including consultants and think tanks).
2. Opinion–based evidence (including lobbyists/pressure groups).
3. Ideological evidence (party think tanks, manifestos).
4. Media evidence.
5. Internet evidence.
6. Lay evidence (constituents’ or citizens’ experiences).
7. Street evidence (urban myths, conventional wisdom).
8. Cabbies’ evidence.
9. Research evidence.
Source: Phil Davies, former Deputy Chief Social Researcher, 2007.

Classic British cynicism this list may be. A caricature of reality it may be. Satire it must be. And it is probably all of the above. Only it is also alarmingly close to the truth.

For a decade or more I have worked with policymakers a lot and I would say that the list and the ranking of sources are accurate. It may not be what policymakers say they want. Many are keen to involve themselves in evidence-based policy but very few of them know where to get the evidence or how to evaluate it. They are easily swayed by ‘evidence’ sourced from within their everydayness, and that often includes the Uber driver.

They are not familiar with the peer-reviewed literature. They are not avid readers of systematic reviews and none of them knows how to estimate a likelihood.

The reality is that most of them do not have the tools to separate opinion from evidence.

It is a huge problem for me and, I suspect, for you too.

The policies that become the laws that determine what we can and cannot do, what society allows and tolerates and the big decisions on how we use or abuse the natural resources that we rely on for our wellbeing should be firmly grounded in evidence, not opinion.

The problem with Mr Davies’ list is that eight of the nine sources are contaminated by opinion. The ‘evidence’ may or may not be based on fact and could cease to be evidence altogether when all it is based on is the worldview of Joe citizen.

Opinion, a view or judgement formed about something, not necessarily based on fact or knowledge

Arguably far too many of our laws are judgement calls that have little or no evidence to back them up. A law to protect the koala because it is going extinct when there is no evidence for this peril.

Here is another certainty to add to taxes, crowded trains and coffee. Policymakers will not use real evidence.

Why?

Because they are not trained in how to tell the difference between what they are exposed to and the truth. In their minds, the two are muddled and confused to the point of being indistinguishable.