additional cause reservationadditional cause reservation - - A level III reservation in the categories of legitimate reservation that is used by a person scrutinizing a sufficiency-based logic diagram to question whether the stated cause(s) is(are) sufficient to fully account for the stated effect. A justifiable additional cause will have a significant impact on the stated effect.
Example: The diagram on the left below is read If 10 My car gets very poor gas mileage then 20 I prefer to take the bus to work. A scrutinizer may use the additional cause reservation to suggest that, 15 I like to read on my way to work, could also be a legitimate cause of preferring to take the bus. The diagram on the right is read as follows: If 10 My car gets very poor gas mileage then 20 I prefer to take the bus to work. If 15 I like to read on my way to work then 20 I prefer to take the bus to work. The two independent causes are described as a magnitudinal 'and' connector.
Perspective: A legitimate additional cause will tighten the logic underlying the observed effect and more fully explain its magnitude. Neither cause by itself can fully account for the magnitude or extent of the effect. A scrutinizer may propose an additional cause and the diagram presenter may accept it if its impact is significant. The additional cause reservation is important because eliminating only one of multiple independent causes will not overcome the effect entirely.