Image credit: Nemo (Pixabay)How can different knowledge components, such as scientific evidence, clinical expertise, and patient preference, within the evidence-based medicine (EBM) framework be combined? Do trustworthy decisions fall out as clear-cut conclusions as part of an algorithm when an EBM approach is used? Eivind Engebretsen, Nina Køpke Vøllestad, Astrid Klopstad Wahl, Hilde Stendal Robinson and Kristin Heggen use the four stages of knowing presented by Bernard Lonergan to show that interpretation is a central feature of EBM when combining the three components of the EBM model to reach a clinical decision.

During the last 20 years there has been an increased focus on evidence-based practice within medicine and health care. Evidence-based medicine (EBM) may be defined as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients”. The goal of EBM is, according to Sackett, the integration of: (a) clinical experience and expertise, (b) scientific evidence, and (c) patient values and preferences to provide high-quality services.

Based on this and similar models, knowledge management systems have been developed to help clinicians to access and make use of research knowledge. Systematic reviews and clinical guidelines are key tools in developing an accessible and adequate knowledge base. The Cochrane Collaboration has provided methods for systematic reviews of clinical trials as well as frameworks to distinguish between different kinds of research evidence and to evaluate the quality of the studies. However, a weakness of the EBM is the lack of guidance on how to combine the main knowledge components of the model. The EBM literature says little about how to create a fruitful interaction between research, clinical expertise and patient preferences.

If the model does not provide sufficient instruction on how to combine the three areas of knowledge, the consequence may be that doctors using the model either undermine clinical expertise and patient preferences altogether or combine the sources in an ad hoc and random way. In a recent paper in the Journal of evaluation in clinical practice entitled Unpacking the process of interpretation in evidence-based decision making, we aim to make explicit the often implicit interpretational work involved when scientific evidence, clinical expertise and patient preferences are combined. We believe that better awareness about this process of interpretation can promote better and more trustworthy decision making.

In order to open the black box of evidence based decision making we draw on a four step conceptual framework developed by the Canadian philosopher Bernard Lonergan. According to Lonergan every act of knowing involves the following steps or levels of cognition: (1) recording of data (sensation); (2) interpretation of data (understanding); (3) weighing of interpretations (judgement); and (4) choice of action (deliberation).

ebmSource: Engebretsen et al. (2015) Unpacking the process of interpretation in evidence-based decision makingJournal of Evaluation in Clinical Practice

Let us imagine a case first developed by Goldman and Shih about two patients, Mr A and Mr B, who are diagnosed with identical tumours treatable either with radiation therapy applied daily over a period of 4 to 6 weeks or with oral chemotherapy taken at home. What is the optimal treatment for Mr A and Mr B?

The first step that needs to be taken is the recording of data. Research evidence tells that the survival rate after 5 years is 86 % with chemotherapy at home and 92% with radiation at the hospital while treatment at home shows slightly better results on quality of life parameters. However, as Lonergan reminds us, this information is not evidence in the sense of providing a direct answer to the question about Mr A and mr Bs optimal treatment. The evidence is data, the “known unknown” which sets off his interrogation for answer: What does the evidence mean?  How does it concern the doctors’ decision for individual treatment?

Having recorded all relevant data, the doctor must pass on to the interpretation of the data, which is the second stage in Lonergan’s model. Now, the doctor unpacks the meaning of the research evidence through critical questioning and through these questions the scientific evidence, clinical experience and patient preferences are combined. The doctor’s experience from similar cases indicates for instance that contextual factors might influence on the treatment, so he asks: What do I know about the life situation of the two patients? He notices one important difference: Mr A has a partner who drives him to the hospital for treatment while mr B lives alone and needs to take the bus. Confronting Mr B with this fact, the doctor discovers that the patient has a strong wish to receive treatment at home since the bus trip would interfere with his daily activities. This raises a new question concerning the application of the research evidence: Do mr B have the motivation to take the bus to the hospital every day, something which is required to have an effective treatment? Should the research evidence be applied differently on patient A and B?

Passing now to the third stage in Lonergan’s model, the doctor needs to weigh his interpretation by comparing it with the data that started off the process. He considers the high 5-year survival rate for both treatments and the slightly better results on quality of life measures with home treatment as arguments in favor of his understanding that mr B would benefit from chemotherapy and at the same time continue with activities important to him. On the other hand, mr A could use radiation without interfering too much with his life and therefore possibly profit from the somewhat higher survival rate.

In the fourth and final step the doctor switches focus from facts to values, from what he knows to what he should do, and new questioning is necessary: Say that mr B is a 76 year old man who lives alone and quite far from the hospital, which steps must be taken to ensure that he manages his medication correctly? The doctor needs to deliberate on this and similar questions in order to arrive at the best available treatment.

Lonergan’s four drivers of knowing provide a tool for facilitating knowledge translation between the three sources in EBM. By using the model, the doctor can combine the sources in a systematic way. The doctor’s understanding of the research evidence comes about through critical questioning in which both clinical experience and patient preferences are put into use. Furthermore, the model can be used to document the different cognitional steps involved in the process.

This blog post is based on a paper in the Journal of evaluation in clinical practice entitled Unpacking the process of interpretation in evidence-based decision making (2015).

Note: This article gives the views of the author, and not the position of the Impact of Social Science blog, nor of the London School of Economics. Please review our Comments Policy if you have any concerns on posting a comment below.

About the Authors

Eivind Engebretsen is a professor of health science with emphasis on the philosophy of science at the Institute of Health and Society, University of Oslo. He is interested in health communication and knowledge translation and the philosophy of evidence based medicine.

Nina Køpke Vøllestad is a professor of health science and chair of the Institute of health and society, University of Oslo. She has a background in natural sciences and physiology and her research has mainly been on musculoskeletal disorders.

Astrid Klopstad Wahl is a professor of health science at the Institute of health and society, University of Oslo. She has a background in nursing and is interested in patient education and other complex interventions within medicine and health care.

Hilde Stendal Robinson is a senior researcher at the Institute of health and society, University of Oslo. She is a physiotherapist and her research has mainly been on musculoskeletal disorders.

Kristin Heggen is professor and vice-dean at the Faculty of Medicine, University of Oslo. Her background is in nursing, pedagogy and social science and she is interested in the interaction between knowledge and power in health care.

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