The demand from our universities, our funders and our government that our research impact on society by changing policy and practice, has brought researchers into ever-greater contact with an increasing-variety of ‘non-academic users’. This raises tensions. In another post, Heather discussed how our research got lost in translation between us, as researchers, and a journalist. In this post, she looks at how we’ve found that we have a different conception of evidence than that which predominates among policymakers.