I must say, Hasherucf, your googling skills seem a little poor, despite Leaddie urging you to 'try harder'.
3 minutes of googling led me to, for example, an archived post on the US Defense Acquisition Portal by the Director of Logistics and Sustainment Centre, in which he commends for reading an article in Sport Aviation Magazine entitled “The Waddington Effect: More Maintenance Isn’t Necessarily Better”. The Director comments:
The author offers interesting perspectives on the history of Reliability Centered Maintenance (RCM), including the once-classified work by H.C Waddington and his British Coastal Command Operational Research Section colleagues during World War II. In it, he also cites a separate, yet equally compelling article in the September 2010 Bulletin of Military Operational Research Phalanx Magazine entitled “ The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness”, as well as a pioneering 1978 RCM report written for the Department of Defense entitled ”Reliability Centered Maintenance”, by F. Stanley Nowlan and Howard F. Heap.
The “The Waddington Effect, C4U-Compliance, and Subsequent Impact on Force Readiness” article is available here:
http://cmapspublic.ihmc.us/rid=1HTKPYHY3-10D9MZ0-11ML/ I quote but a few paras:
… Conventional wisdom held that, if more preventive maintenance events were performed on each aircraft, fewer problems would exist – and potential problems could be caught and fixed – and thus the effectiveness of the fleet would surely improve. Conventional wisdom was, as is so often the case, wrong. It would take Conrad Hal (C.H.) Waddington and his Operational Research team to prove just how wrong.
C. H. Waddington (1905-1975) is best known, today, as one of the first developmental geneticists – and as a person who did not believe that genetics, embryology, and evolution were separate sciences. But his interests and contributions covered a much broader spectrum. Those individuals involved in the field of Artificial Intelligence recognize him, or should, as one of the pioneers of the optimization technique designated as Genetic Algorithms. Those in the military recognize him, or should, as one of the leaders in the development of a new, unorthodox, and – at one time – highly suspect (i.e., by the military) approach to military planning, both strategic and tactical.
…
..[B]efore scurrying about to provide a slick briefing on a scheme that might or might not work, Waddington and his team had the audacity to stop and think. They requested and analysed the supporting data, talked with maintenance crews, and took time to carefully and personally observe actual maintenance events (a decision quite unlike that of too many “analysts” who prefer to remain in their warm and comfortable offices, poring over and processing data provided from “the outside”). Furthermore, rather than getting the wrong answer, or the politically correct answer, fast, these Operational Researchers trod the lonely path of seeking a proper, effective, and practical answer.
…
The conclusion Waddington and his group reached … was, in Waddington’s own words, that “inspection tends to increase breakdowns, and this can only be because it is doing positive harm by disturbing a relatively satisfactory state of affairs. Secondly, there is no sign that the rate of breakdown is beginning to increase again after the 40-50 flying hours, when the aircraft is coming due for its next [preventive maintenance event].”
…
In other words the Waddington Effect is defined as a “spike” in the number and frequency of unscheduled events “closely” following a scheduled event – followed in turn by a gradual decline in the a rate of occurrence of unscheduled events to a “more normal level,” until a repeat of this same, troublesome effect following the next scheduled maintenance event.
…
[And just to support Leaddie’s earlier post: Once these recommendations were implemented the effective size of the British Coastal Command air fleet was increased by more than 60 percent! In other words, a change in maintenance protocols and their documentation (as motivated by the identification of the Waddington Effect) was as effective (and far less costly or time consuming) as the allocation of an additional 60 percent more aircraft….
[My bolding]
I also note but a few paragraphs from the latter report (available here (WARNING: IT IS A BIG FILE):
http://reliabilityweb.com/ee-assets/...n_and_Heap.pdf
One of the underlying assumptions of maintenance theory has always been that there is a fundamental cause-and-effect relationship between scheduled maintenance and operating reliability. This assumption was based on the intuitive belief that because mechanical parts wear out, the reliability of any equipment is directly related to operating age. It therefore followed that the more frequently equipment was overhauled, the better protected it was against the likelihood of failure. The only problem was in determining what age limit was necessary to assure reliable operation.
In the case of aircraft it was commonly assumed that all reliability problems were directly related to operational safety. Over the years, however, it was found that many types of failures could not be prevented not matter how intensive the maintenance activities. …
A major question still remained, however, concerning the relationship between scheduled maintenance and reliability. Despite the time-honoured belief that reliability was related to the intervals between scheduled overhauls, searching studies based on actuarial analysis of failure data suggested that the traditional hard-time policies were, apart from their expense, ineffective in controlling failure rates. This was not because the intervals were not short enough, and surely not because the teardown inspections were not sufficiently thorough. Rather, it was because, contrary to expectations, for many items the likelihood of failure did not in fact increase with increasing operating age. Consequently, a maintenance policy based exclusively on some maximum operating age would, no matter what the age limit, have little or no effect on the failure rate. …
[My bolding]
In short: Belief versus science and hard data.
Upon which do you reckon periodic calibrations of e.g. compasses and fuel gauges on private aircraft in Australia have been mandated?