Noonan, as I wrote below, decided not to attempt to compare levels of corruption across time and space. His explanation is worth quoting at length, as it gets into a lot of the problems surrounding attempts to quantify corruption. (Note that he describes the practice of indexing corruption to numbers of convictions as a “mistake.”)
What I have resisted is a temptation almost equally irresistible–to quantify. Modern moral argument, not to mention sociology and criminology, depends heavily on quotable numbers. When the subject is bribery, an economic transaction, it seems that numbers should be available. Tourists and journalists are very free in judging that a society is “corrupt” or “very corrupt.” Historians and political scientists have not been far behind them. Surely, it may be supposed, the confident judgements that have often been made rest on a foundation of figures.
Quantification is conceivable. It has never been systematically attempted. There are no existing sets of figures by which one could conclude that the Roman Empire, for example, was more or less corrupt that the British Empire or the United States. In the absence of this kind of data it is wrong, I believe, to create an illusory certainty by using comparative terms.
Judgment about corruption in a society need not rest on a statistical basis. But with bribery several factors operate to make unquantified judgment difficult.
First,* the act is criminal and consensual; the victim where there is one is not made aware of the arrangement as it affects his case; consequently a number of acts of bribery remain secret and undiscovered.
Second, accusations of bribery are often politically motivated or are made in order to satisfy certain social or psychic needs; one cannot judge from the accusation along whether acts of bribery have actually occurred.
Third, the amount of legal attention bribery receives is misleading. One society may be uncensorious of most reciprocities with its officeholders; there may be no legal response to them a all, and the appearance will be given of integrity everywhere. A different society may define bribes, legislate against bribetakers, and prosecute bribery in such a way as to suggest that the crime is ubiquitous. A common mistake is to use the number of laws enacted or convictions obtained as an index of corruption.
Fourth, some critics have strong inclinations to exaggerate the corruption of their own day, and others have strong inclinations to denigrate past times or aliens or members of another race, religion, or class. Their criticisms will then be used as evidence that corruption is worse now or worse then, or worse with certain groups than others. Impassioned complaint will function as though it were hard evidence.
Fifth, there is the fallacy of the perfectly corrupt man–the belief that vices are linked and that unless a man is thoroughly corrupt in every aspect he can be no bribetaker or bribegiver. Moral judgment is held at bay by the kindly family man or illustrious genius who is also a taker or giver of bribes. Francis Bacon, Samuel Pepys, Warren Hastings are not merely respectable; they are heroes–respectively the founders, in the view of their admirers, of British science, the British navy, and British India. Bacon was a bribee by the law as actually enforced; Pepys a bribee by his own measure; Hastings a bribee by the law that was being made. Apologists by the score have hesitated to give their bribetaking its proper name. As for bribers, judgment has always been even more charitable, the underlying assumption being that they are the victims of extortion. When the persons involved have been preeminently just, judgment has often been entirely suspended. Who thinks of Thomas Becket or John Quincy Adams as giving bribes? The fallacy of the perfectly corrupt man prevents seeing bribery in transactions which, measured by at least one of the standards in use in their own time, were corrupt although executed by men of otherwise eminent virtue.
Finally, there is great difficulty in accepting a society’s own standards when one approaches the society as a traveler or as a historian. Bribes are a species of reciprocity. Human life is full of reciprocities. The particular reciprocities that count as bribes in particular cultures are distinguished by intentionality, form, and context. What is a bribe depends on the cultural treatment of the constituent elements. The observer outside the culture, like the cynic or rigorist within it, is inclined to see the conventional differences as arbitrary and to reduce all reciprocities of a given kind to bribes–to treat, say, any gift to an officeholder as a bribe. Doing so, the outsider imposes his own standard and reaches a judgment that is unreasonable if the culture’s own norms are used.
These major reasons for mistake–the rarity of proof of actual bribery; the abundance of accusations; the misleading impressions given by legal activity in its regard; prejudices of many kinds; the fallacy of the perfectly corrupt man; and the reductionism that eliminates conventions and looks only at function–mean that broad generalizations about the amount of bribery in a society must be made with caution and with caveats and without great confidence in their reliability.
*I’ve broken items 1-4 on this list into separate paragraphs for easier reading.