In Analysis and Testing In Accident Reconstruction, accident reconstruction expert witnesses at Technology Associates explain the nature of engineering analysis:
Persons with no training in engineering are generally unaware of the nature of engineering analysis, and so tend to assume that testing, as a means of determining the causation of accidents, is a dominant tool of the engineer. In the following examples, we shall undertake to explain the nature of engineering analysis, and to show that it is more basic than testing because testing without analysis is meaningless. Further, while analysis is always necessary in accident reconstruction, testing is only sometimes necessary.
Consider, for example, a flight of steps in which the tread of each step (the horizontal surface) is only 6 Inches deep (in the direction from front to back). Since the shoes of most persons are considerably greater than 6 Inches in length, the toes of a descending adult will tend to overhang the tread by a substantial amount, especially since It Is not to be expected that the heel will always be placed as far back as possible, thereby increasing the overhang all the more. The result will be that the footing will not be as secure as If the tread were, say, 10 inches deep. Thus, if a person has fallen while descending the 6-Inch-deep steps, the fall may be ascribed to the inadequate depth with reasonable probability (providing of course that there is no other contributing reason for the fall).