Lloyd published several of his lectures. In his Two Lectures on the Checks to Population he introduced the concept of the overuse of a common by its commoners, which was later to be developed by the economist H. Scott Gordon and later still by the ecologist Garrett Hardin and termed by Hardin "The Tragedy of the Commons". However, Hardin's use of Lloyd's example has frequently been misunderstood, leading him to later remark that he should have titled his work "The Tragedy of the Unmanaged Commons". The key passage in Lloyd's work is:
"If a person puts more cattle into his own field, the amount of the subsistence which they consume is all deducted from that which was at the command, of his original stock ; and if, before,there was no more than a sufficiency of pasture, he reaps no benefit from the additional cattle,what is gained in one way being lost in another. But if he puts more cattle on a common, the food which they consume forms a deduction which is shared between all the cattle, as well that of others as his own, in proportion to their number, and only a small part of it is taken from his own cattle. In an inclosed pasture, there is a point of saturation, if I may so call it, beyond which no prudent man will add to his stock. In a common, also, there is in like manner a point of saturation. But the position of the point in the two cases is obviously different. Were a number of adjoining pastures, already fully stocked, to be at once thrown open, and converted into one vast common, the position of the point of saturation would immediately be changed".
In his Lectures on Population, Value, Poor Laws and Rent he introduced a concise and complete statement of the concept of diminishing marginal utility, and connected demand to value, but he presents neither derivation nor elaboration. Still this contribution places him clearly in the ranks of the Oxford-Dublin school of proto-Marginalists.
Major works of William F. Lloyd
Lecture on the Notion of Value, as distinguished not only from utility, but also from value in exchange, 1833.
Two Lectures on the Checks to Population, 1833.
Four Lectures on Poor-Laws, 1835
Two Lectures on the Justice of the Poor-Laws and One Lecture on Rent, 1837.
Lectures on Population, Value, Poor Laws and Rent, 1837.