Since the passage of the California Fair Pay act in late 2015 (effective January 1, 2016) and its recent amendments, many employers and commentators have criticized the statute for imposing a vague and dangerous standard on California employers.
The California Fair Pay Act replaces the former “equal work” standard of the Equal Pay Act with a “substantially similar” standard. The California Fair Pay Act (Labor Code section 1197.5) states: “(a) An employer shall not pay any of its employees at wage rates less than the rates paid to employees of the opposite sex for substantially similar work, when viewed as a composite of skill, effort, and responsibility, and performed under similar working conditions …”. 
Some adrenalized commentators have said that any effort to actually conduct this analysis is a fool’s errand. The standard is so vague and shapeless that it is functionally meaningless until a court sharpens the standard with defined tests and definitive holdings. Other commentators suggest that employers abandon any attempt to determine if any two types of work are substantially similar to one another (an analysis required by the statute) and instead focus on the second half of the statutory analysis, which allows employers to justify wage disparities (along race or gender lines) on the basis of a bona fide factors other than sex or race.
While it is true that courts have not yet ordained a specific analysis on how to determine substantially similar work, the statutory standard is not so vague as to defy either analysis or application. Legislative examples propose that under this standard a male school janitor and a female hotel housekeeper may be engaged in substantial similar work.
Even if the standard were so vague as to defy application (and I don’t believe it is) employers are well served to act reasonably and based upon a good faith and reasonable interpretation of the law. Yes, a court may later hold that some part of any analysis used is incorrect, but the use of a reasonable analytic process (before any court decision considering the law) will likely place an employer in a better position than a company that has skipped the first step of the required analysis.
To read this full article and a general approach to conducting the “substantially similar” work analysis, click here.