Weighing the Evidence

Abstract

The optimal of existing research evidence to guide design decisions is referred to as evidence-based design. Sackett, Rosenberg, Gray, Haynes, and Richardson's (1996) well-known definition of evidence- based practice for any discipline is conscientious, explicit, and of current best evidence in making decisions... (p. 71). This definition emphasizes the importance of using evidence, and the judicious use also implies the importance of respecting other factors in design decision making, such as a client's preferences, the project budget, the culture of an organization, and even the community context of the project's location.Evidence-based design is a relatively new science, and we have far more need for evidence than we have available research findings. In fact, there are far more urban myths (accepted truths with no evidence) about the effects of specific design features on outcomes than there is real research evidence. So who and what should we believe when making the million- and sometimes billion-dollar decisions that can affect healthcare delivery for many years to come? We are obligated to build the evidence depository with credible and replicable findings from formal research done using our current projects, disseminating these findings in journals such as HERD and at national professional conferences, diffusing the evidence in design meetings and team discussions, and then adopting the evidence rather than our traditional routines and practices to guide decisions in future projects.Research implementation or utilization is the heart of evidence-based nursing (van Achterberg, Schoonhoven, & Grol, 2008). Everett Rogers' theory for the diffusion of innovation (Rogers, 2003) explains the implementation of research evidence or findings and the rate of adoption of new findings. It indicates that the adoption of new evidence is affected by (1) how credible the evidence seems; (2) the users of the evidence with all of their biases and perceived barriers to implementation; (3) how widely communicated the findings are; and (4) the social system in which the evidence will be used. Thus, while the research findings may be clearly known, some will be early adopters of the new findings, whereas others may be late adopters who wait to see how others implement the new ideas into their building designs. Most important to early adoption is the availability of credible, reliable, and valid research findings.Weighing the EvidenceLet's face it: not all evidence is created equal. Some of the evidence regarding the effect of specific design features on patient outcomes or organizational performance is weightier than other evidence, meaning that we can be fairly sure that the findings can be used to guide decisions in other design projects. What is it that makes some evidence more reliable? How do we analyze or appraise research findings to determine that they are worthy of implementation? These are critical questions, considering that design decisions have costs associated with them. We want to make these decisions based on the best possible evidence available, not on someone's opinion or an urban myth.Hierarchies or Levels of EvidenceHierarchies provide a guide to the strength of available evidence regarding the research methodology used to measure the effect of design features on specific outcomes and the quality of the research in its elimination of inherent biases. Evans (2002) states, Hierarchies aim to provide a simple way to communicate a complex array of evidence generated by a variety of research methods... and they provide a level of trust that can be placed on the recommendations, or alert the user when caution is required (p. 79). Medicine and nursing have developed hierarchies that rank the systematic review of multi-site studies at the highest level of reliability and expert opinion, case studies, and descriptive studies at the lowest level. When making decisions to treat or not to treat, we want to evidence gained from the systematic review of multiple studies conducted at multiple sites with rigorous research to minimize the possibility that the findings occurred by chance. …