Media are important. Especially the media we trust. One might express the effect of a piece of journalism (J) about, say, a particular drug or food, as a factor of media authority (A), multiplied by the size of audience (D), divided by the availability of credible alternative sources (S).

The more of the latter which are accessible to the audience, and thus the greater the challenge to the “truthiness” of (J), the lesser the impact on individual and collective behavior. Where people trust the news source, and the issue is complex, and alternative analyses are not easily sourced, the effect is greater.

Some time ago I wrote about the impact of media coverage of the discredited Andrew Wakefield’s research on the MMR vaccine. Thousands of parents came to believe, mistakenly, that their children were at risk from participation in the MMR vaccination program, and today as a direct result we are seeing unprecedented levels of measles infection in Australia and overseas.

Wakefield’s fraudulent alarms about MMR must have been true, they must have assumed, because they read it in a paper, or heard about it on a TV channel they trusted.

The ABC has been in the critical spotlight this week for a documentary it ran in October 2013 about the effectiveness of statins in lowering cholesterol and the risk of heart disease. Mark Scott has already acknowledged that the Catalyst program breached the ABC’s impartiality rules.

This week, University of Sydney researchers claimed that 60,000 Australians had stopped taking their statins in the wake of the program – 10% of those on the medication. The impact of this could be an increased incidence of stroke and heart disease in the future. People could die, in short.

This reminds me of the BBC’s coverage in 1995 of the potential risks associated with a new kind of contraceptive pill which had come on to the market. Reporting research that the pill increased the risk of thrombosis for women by a factor of two, the BBC sparked a health panic of the classic type. Women stopped using the contraceptive in significant numbers.

The result was a short-term rise in abortions of 9%, and a longer term rise in deaths in childbirth and other illness caused by pregnancy – far from risk-free even in these days of high-tech medicine – which in terms of harms caused to women far outweighed the likely impact of the contraceptive.

I recall listening to that story on the BBC’s flagship radio news show, on my regular drive home from work, with its alarming picture of the risk to women doubled by what had previously been regarded as a harmless contraceptive. What I hadn’t realised, because the report didn’t say, was that the risk to begin with was so small as to be negligible, and that the risk of pregnancy to a normal healthy woman was higher than that from thrombosis associated with this particular pill.

The case remains a classic in teaching journalism students how not to report scientific research.

The lessons from the ABC’s statins story, like that of the BBC two decades previously, are twofold. First, journalists – and especially journalists in public service media – have to get better at reporting science. In this field of coverage, mistakes and errors can have real consequences on people’s lives.

Second, as audiences, we must never assume that just because the ABC says it, or the BBC, or indeed The Australian or any other respected news source, it must be true. News is about stories, remember, and every story has more than one side to it. Increasingly, our news media have neither the time, nor the resources nor – it seems – the inclination to engage with that complexity.

By Brian McNair, Professor of Journalism, Media and Communication at Queensland University of Technology. This article was originally published on The Conversation. Read the original article.