Halstead effort

Halstead effort is one of a number measurements developed by Maurice Halstead to determine the mental effort required to develop or maintain a program. The lower a program's Halstead effort, the simpler the program is to change.

Rational® Asset Analyzer calculates Halstead effort for COBOL and PL/I programs using the following formula:

E = D * V

D = Difficulty, calculated as

D = (n1 / 2) * (N2 / n2)

V = Volume, calculated as

V = N * (LOG2 n)

These formulas use the following terms:

n

Program vocabulary, calculated as

n = n1 + n2

n1

The number of distinct operators. Rational Asset Analyzer uses the number of distinct statement types, as known to the product, occurring in the program.

n2

The number of distinct operands. An operand can be either a variable or a literal. Rational Asset Analyzer uses the number of referenced distinct data elements and literals.

N

Program length, calculated as

N = N1 + N2

N1

The total number of operators. Rational Asset Analyzer uses the total number of statements in the program.

N2

The total number of operands. Rational Asset Analyzer uses the total number of references to data elements and literals.