Henderson-Sellers defines Lack of Cohesion in Methods as follows. Let:
M be the set of methods defined by the class F be the set of fields defined by the class r(f) be the number of methods that access field f, where f is a member of F <r> be the mean of r(f) over F.
Then:
Lack of Cohesion in Methods = <r> - |M| 1 - |M|
Note 1: I have only included methods if they access at least one field.
Note 2: I have only included fields if they are accessed by at least one method in the class.