In order to discuss the decline affect, we must be clear what we are talking about - both in terms of how the scientific method operates and what the decline effect indicates. Lehrer does an excellent job of breaking down the idea in the first of his New Yorker pieces as follows:
Before the effectiveness of a drug can be confirmed, it must be tested and tested again. Different scientists in different labs need to repeat the protocols and publish their results. The test of replicability, as it’s known, is the foundation of modern research. Replicability is how the community enforces itself. It’s a safeguard for the creep of subjectivity. Most of the time, scientists know what results they want, and that can influence the results they get. The premise of replicability is that the scientific community can correct for these flaws.
But now all sorts of well-established, multiply confirmed findings have started to look increasingly uncertain. It’s as if our facts were losing their truth: claims that have been enshrined in textbooks are suddenly unprovable. This phenomenon doesn’t yet have an official name, but it’s occurring across a wide range of fields, from psychology to ecology. In the field of medicine, the phenomenon seems extremely widespread, affecting not only antipsychotics but also therapies ranging from cardiac stents to Vitamin E and antidepressants: [Professor of psychiatry at the University of Illinois at Chicago, John] Davis has a forthcoming analysis demonstrating that the efficacy of antidepressants has gone down as much as threefold in recent decades.
Lehrer seems to point to the decline effect being most likely a product of the combination of manipulations and inconsistencies of study sample sizes, etc, on the part of scientists in order verify their suspicions taken with a statistical error produced by using that semi-arbitrary old chestnut:
α = 0.05
The question becomes, with certain types of errors - most specifically manipulations by researchers, consciously or unconsciously to get the results they want perhaps acting as known errors, to what extent do unknown errors play into the decline effect? With science being our best device for understanding and interpreting the world around us, to what extent does the decline effect seem to question the very basis that we are capable of carrying out objective science altogether? Certainly, it must beg questions about the efficacy of almost any study.
Despite this, we also have thousands of studies in which the science and data do some to be rigorous, results are constantly reproducible with similar statistical spreads and results appear to be intuitively right, in that they reflect what we see through less rigorous forms of observation. Certainly, it would be fools errand to use the decline effect as a rationale to dismiss science as a whole as a flawed ontological mechanism. Importantly, those elements of science, such as climate change or evolution that are more commonly dismissed for ideological reasons tend to be those that have been the most widely studied and which have shown repeated and non-declining confirmation
What needs to be understood about the decline effect is, what can be learned from it in order to determine objectively what is going wrong and thus how to correct for it. Certainly, an adjustment of the α used as the norm may be an important step, as would still tighter controls upon methodology to prevent insertion of researcher bias are important first steps, but the phenomena of the decline effect itself needs to be more widely studied. Thus far, meta-studies of the studies that have 'suffered' from the decline effect appear inconclusive. This however, merely speaks to the need for further study.
As humans, we have a genetic tendency to want to intuit things. We appreciate the observable and tactile and our brains seek out patterns that appeal to us emotionally or aesthetically. Science does not operate under the same set of limitations, however as science is conducted by humans, the occasional error will be introduced. It is the roll of the scientific method to limit the number of errors that can occur, however, as Popper noted, definitive Truth remains unknowable, and we must perpetually falsify (in the Popperian sense) those truths that we do arrive at as a means of bringing us ever closer to that unreachable position of what is.
The decline effect is perhaps best interpreted as a feedback mechanism. It illuminates certain shortcomings in our current modus operandi and demands of us that we falsify and refine anew. We must perpetually destroy the intellectual frame-works that we build in order to better understand. Science exists as a method of discovery rather than speaking to absolutes. This process is almost, to a the definition postmodern, in its rationale.‡ We should not despair of this, but rather to respond and learn as such are the wages of discovery.