A theoretical analysis of the phenomenon of diminishing marginal productivity of gangs employed for (un)loading a vehicle

The experience of (un)loading ships and other vehicles in sea ports shows that the rate (i. e. amount cargo being (un)loaded (from)onto a vehicle per time unit) does not increase direct proportion to number gangs employed; accordance with law diminishing marginal productivity each additional gang adds less (un)loading. Despite its importance operations planning, this phenomenon has been given careful consideration clear explanation literature related port operations. This paper attempts fill gap by offering theoretical for why decreases addition extra gang. suggests two reasons behind phenomenon: interference effect, conjunction effect. Both these effects are due fact is deterministic but stochastic process. Each examined both quantitatively qualitatively.