Anonymous: I.J. Good?
This paper appeared in a mostly serious, partly facetious collection. The Editor, I.J. Good, was a highly productive and moderately quirky Bayesian, and it's possible that Good himself contributed to this list.
Anon. 1962. Bloggins's working rules. In Good, I.J. (Ed.) The Scientist Speculates: An Anthology of Partly-Baked Ideas. London: Heinemann, 212--213.
[p.212]
Murphy's edict -- if something can go wrong it will.
If a problem has less than three variables it is not a problem. If it has more than eight, you cannot solve it.
Parkinson's Laws state:
(i) Work expands to fill the time available for its completion, especially when it is interesting.
(ii) A man starts to lose his grip five years before retirement age, whatever this may be.
Hartree's Law states that whatever the state of a project, the time a project-leader will estimate for completion is constant. A task always takes twice as long as one might reasonably expect.
All reports require three drafts.
The 20:80 rules: 20 per cent. of the people drink 80 per cent. of the beer. It is prudent to assume the same concentration of effort elsewhere, and Holt's Rule to forecast time series states:
New forecast $=$ 0.2 (Last result) + 0.8 (Last forecast).
When there are unknown scale factors, assume a 0.70 power law.
Numbers in real life usually have a 25 per cent. coefficient of variation and rarely less than 10 per cent. Data usually have at least 1 percent. of gross errors. This applies to people too.
[p.213]
The best experts resist innovation, for they wish to remain experts, and they are right only three-quarters of the time.
The variance of cumulative chance events is practically infinite.
Edie's Limit. Pooled Services may be more effective in theory, but they are soon degraded by difficulties of switching and scanning. Edie found 4--6 channels the most efficient group size for toll booths. The same number must often apply elsewhere.
Anyone more than two years younger than oneself is inexperienced. Anyone more than five years older is past his best.
Any useful classification has 3--6 sub-categories, but a thirty-fold division provides a fine monument to hard work.
Really top brass takes one year to make up its mind in matters in which you are interested.
Do not ask questions on which people have no real opinions, or which they will not answer truthfully. Socratic dialogue is more potent than any arithmetic.
There are never less than three conflicting criteria of merit. At best, operational research is nearly right.
Life is
(i) Discrete.
(ii) Non-linear.
(iii) Non-zero sum.
(iv) Non-commutative, and positively irreversible.
(v) Multiplicative rather than additive; the log normal distribution is more normal than the normal.
One nearly always has prior knowledge, but optimisation? It is a delusion. Probabilities are always conditional -- very conditional.
There are no decision rules to choose decision rules.
The only practical problem is what to do next.
The art of being correct lies in making the weakest possible statements.
[ends]
Notes by NJC:
Edie, Leslie C. 1954. Traffic delays at toll booths. Journal of the Operations Research Society of America 2(2): 107--138.
Leslie C. Edie (1914--1990) was an early pioneer in operations research and transportation science.
Douglas Rayner Hartree (1897--1958) was a mathematician and physicist who contributed to numerical analysis and its application to atomic physics and to the development of computing machinery.
Charles C. Holt (1921--2010) is known for modelling and forecasting methods using exponential smoothing.
Cyril Northcote Parkinson (1909--1993) was a naval historian and author of many books, most famously advancing Parkinson's Law.