It is known that it takes a long time for an evidence to be applied in practice. But how long is that time? Though the evidence behind the claim is uncertain, it is a commonly held belief that it can take up to 18 years for research evidence to be applied in practice.
Both evidence and practice are progressive and accumulate over time. Cumulative evidence influence cumulative practice. Thus, both evidence and practice are always changing i.e. they are moving targets. As a result, an exact match between evidence and practice is not usually expected at a point in time. Rather a general ‘agreement’ between the two is expected. This agreement is between the ‘cumulative and generalizable’ evidence and the ‘widely adopted and implemented’ practice.
Both the generation of generalizable evidence and the adoption of a recommended practice have their own lead times. These lead times differ and each varies among different fields of research and practice. Understanding them is important for effective translation of evidence in to practice.
The lead time for the generation of generalizable evidence is the time from the conception of an important research question to the accumulation of generalizable evidence. Evidence could be obtained from several analytic products. The synthesis of these analytic products accumulates evidence. By the time when the generation new evidence doesn’t add a significant value to the cumulative evidence, one can say the lead time for generation of generalizable evidence is completed. As different parts of evidence are not generated sequentially, this lead time is not the sum of the lead times of the undertaking of independent studies. Rather, it is the sum of the lead time of the generation of the first evidence and the lead time of the accumulation of evidence.
Similarly, there is a lead time for the adoption of a recommended practice. This is the time period between the contemplation of evidence about a recommended practice and the full scale adoption of a recommend practice. There could be several steps between these two ends. A recommended practice may undergo further trials and evaluations before being considered for wider scale adoption. Then policies and guidelines need to be adapted. Implementation of these guidelines also takes some more time.
The lead time for the adoption of a recommended practice may start before the lead time of the generation of generalizable evidence ends. That means there will be an overlap between the lead time of generation of generalizable evidence and the lead time of adoption of a recommend practice. In this case, the lag time, the time between the completion of generation of evidence and the start of its adoption process will be negative.
The lag time between evidence and practice is usually positive. In a research that doesn’t involve potential users, lag times can be very high. It takes time to reach to its target users. The users need time to be aware of the existence of the evidence and understand it. Then the adoption process starts. Evidence about the length of these lead and lag times in limited and more research is needed to address this gap.