Communicating the Evidence

Abstract

The 50-50-90 rule: Any time you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong. 1 Have you thought that after spending considerable effort searching for the best evidence on a specific treatment or diagnosis how much will be lost in translation between yourself and the patient?The words 'guarded' or 'fair' come up a lot in communication with The Practice-Based StudyTo see how often dentists use the word 'guarded' I performed a small study with six experienced clinicians writing out hypothetical restorative dental treatment plans without any prompting as to what I was looking for. Eleven clinical cases were presented, and the clinicians were asked to draft out a letter assessing current dental health and future treatment options for each case. The results were collected and produced twenty-six descriptive terms relating to prognosis/risk and outcome. Chart 1.shows a truncated list of the most common WEPS used: Chart 1. Words of Estimative ProbabilityIn these results, 'guarded' was the third most common term used (18%), and in more specific conversations with the same team of clinicians we agreed that the key words (excellent (95% +/-5%), good (75% +/-15%), fair (50% +/-10%), guarded (25% +/-15%) or poor (5% +/-5%)) related to a quite specific scale of success probabilities. The chart shows quite clearly that the patients had a higher expectation of a successful outcome than the professionals and in relative terms this disconnect increased almost exponentially as the professional prognosis worsened (Table 1.) Medical/Dental EvidenceWhat can we conclude from these preliminary results and is there any evidence out there to support this observation? I would like to first focus on the tendency of the patients to overestimate benefits of treatment and consequently underestimate harms. There is very little specific literature, but I did find two qualitative dental studies and one medical systematic review that illustrates this bias:• Hof et al. 4 found that out of 150 consecutive patients seeking a dental implant, 59% expected it to last a lifetime and 31% at least ten years, and 9% shorter. Patients' estimation of the 10-year implant success rate was 84%.• A qualitative study 5 on public perceptions of dental implants concluded the participants 'expected dental implants to restore the patients' appearance, functions, and quality of life to absolute normality. They regarded dental implants as a panacea for all cases of missing teeth, overestimated their functions and longevity, and underestimated the expertise needed to carry out the clinical procedures.• In 2015 a medical systematic review 6 was undertaken with the objective to 'quantitatively assess patients' expectations of the benefits and/or harms of any treatment, test or screening test'.After reviewing 36 studies, 65% of patients overestimated a treatment benefit and 50% underestimated a possible harm from a treatment. Evidence from other professionsThe Intelligence and National Security community have been work...