Software Measurement is essential for a science Measurement

Software Measurement is essential for a science Measurement - part 1 1

Measurement u “the process by which numbers or symbols are assigned to attributes of entities in the real world in such a way as to describe them according to clearly defined rules” Measurement - part 1 2

Uses of Measurements u assessment u prediction – mathematical model – inherently stochastic Measurement - part 1 3

Measurements u Process measures – GQM - Goal - Question - Measure – e. g. if we want to improve customer satisfaction, measure number of defect reports u Product measures – identify the essential characteristics of document – e. g. LOC, Mc. Cabe’s Cyclomatic Number Measurement - part 1 4

LOC u Why isn’t the Lines of Code measure very useful? u It is not an essential characteristic of software u It is not very useful as a predictor Measurement - part 1 5

Height and weight u Why are height and weight useful in measuring people? Measurement - part 1 6

Height Measurement - part 1 7

Representation Condition u If Fred is shorter than or equal to Bill, then Fred’s height is less than or equal to Bill’s height u if x <= y, then m(x) <= m(y) Measurement - part 1 8

Properties of Measures u Monotonicity u Scale Types – nominal – ordinal – interval – ratio – absolute Measurement - part 1 9

Using Measures u Can we take the average of heights, temps, grades, shoe sizes, jersey numbers? u Can we add two heights, temps, grades, jersey numbers, shoe sizes? u Can we compare ratios of heights, temps, grades, jersey numbers, shoe sizes? Measurement - part 1 10