The main aim of this study was to measure the impact of the format on understanding the key messages of an economic evaluation by non-technical audiences. In addition, the perceived usefulness and acceptability of the formats was also explored. To the best of our knowledge, this is the first study analysing this impact in the context of health economic evaluations. The design of the formats reflected the target audience: for the general public, plain language was used in infographic, text and video format, while for professionals from the healthcare sector, more specialized language was used in executive summary and policy brief formats. A summary of a hypothetical economic evaluation was created for the purpose of this study, intentionally choosing a well-known disease and a situation in which the intervention is more effective and costlier than the comparator. It is, therefore, necessary to calculate the ICER and compare it to the cost-effectiveness threshold. Moreover, conclusions drawn were different for the two patient subgroups according to their age.

For the general population it was observed that participants understood the key messages significantly better from the infographic or plain text than from video-abstract. However, the perceived usefulness and acceptability was better for the video-abstract than for the plain text (not better than for infographic). But, our results also suggest that with the video-abstract, the audience could be wrongly convinced that they have a good understanding of the information. Based on this, the infographic could be a good way to present economic results to this audience, and if we prioritize comprehension over attractiveness, plain text could be an alternative to the infographic.

The specialized public had similar levels of comprehension after reading the executive summary or the policy brief (slightly better for the executive summary), but the policy brief was clearly perceived as more useful and convenient to convey the key messages. Therefore, in the absence of statistical differences in comprehension between formats, a policy brief may be the preferred choice. Interestingly, participants’ background in both populations did not have a significant influence on their objective or subjective comprehension.

Lastly, a relationship was observed between the main endpoints, i.e. objective vs. subjective comprehension, and objective comprehension vs. usefulness. This could indicate that the summaries were well designed and adequate for the target audience, especially in case of the general public. In this audience, our results confirm that having more correct answers relates to higher confidence and also to more usefulness perceived, for all three formats. The false conviction in understanding the results, that the video-abstract format appeared to give the audience, is not necessarily due to the format itself and should be studied further. Subjective comprehension, i.e. the level of confidence, cannot be compared between audiences because the objective questions and formats were different. However, specialists who answered all questions correctly did not show complete confidence in their answers, unlike the general public. Further qualitative research would be needed to clarify the reasons for these findings.

Visualization of information is a key factor in the popularization of technical-biomedical aspects [21]. Infographics have recently been included by the Cochrane Collaboration to present results from systematic reviews [11], in addition to scientific summaries, tables of results and summaries using plain language, as well as other innovative formats such as blogshots. Previous studies have developed similar analyses to ours but focused solely on clinical outcomes, whose conclusions on the comparison of different formats are summarized below. Current evidence about the use of infographic vs. other formats to present information is mixed [13, 22, 23]. There is evidence that the optimal format depends on the audience. For example, regarding systematic reviews it has been proven that professionals prefer information based on text, while the general public is more comfortable dealing with an infographic [13], which is in line with this study’s results. Similarly, when dealing with information about the risk-benefit ratio, parents prefer infographics over text and table [24].

Audiovisual format, such as video format or animation combined with sound, is a new way of communicating with the target population. Video-abstracts can include even more information in a concise format than infographics [25]. Some scientific journals have started offering video-abstracts as well as infographics and simple language abstracts for published articles [15]. This presentation has also been used for informed consent in clinical trials to improve participation and participant comprehension in regard to objectives, methods and potential benefits and risks [12, 26, 27]; and to illustrate information about the risks of an intervention, but without conclusive results [28]. Bredbenner et al. [15] presented summaries of HIV research and concluded that people value audiovisual formats better. In terms of comprehension of the information presented, this format, together with plain language summaries, received higher ratings than other formats. This study confirms that the video format is attractive for the general audience, but it may not be the most effective in conveying the key messages of economic evaluations. A combination of several formats, e.g. infographic and video-abstract, could further improve comprehension, but more research is needed.

It is fair to say that communication with the public extends beyond just simplifying the cost-effectiveness report itself. This also includes transparency about the processes involved in commissioning, conducting, and interpreting economic analyses. The complex task of decision makers to communicate not only the results, but also the methodology and decision-making processes, plays a critical role in ensuring the public’s understanding and trust.

In the health economics field, there has been a lack of evidence on the effectiveness of different summary formats to convey key messages of economic evaluations. To the best of the authors’ knowledge, this study is the first to measure the objective and subjective comprehension of economic evaluation summaries.

One limitation is that the analysis here only identifies which format is better when a research team carefully creates content-identical summary formats following the rules set out by best practice guidelines. There is still further work to be performed to measure the comprehension of different types of economic results presented to specific audiences. Podcast was one type of summary format omitted in this study, but it is gaining in popularity.

Data were collected from a pre-recruited sample, which could differ from the general population in their characteristics, e.g. low representation of lower education levels. However, the randomization guaranteed that the groups were comparable between them. An online survey with a limited number of close-ended questions was used, although other techniques can be used to explore user preferences regarding format, such as interviews or focus groups, typical of qualitative research [29].