Google fought claims that its female employees make less than their male counterparts by outlining the methodology is uses to determine compensation on Tuesday. The company's response comes one day after the U.S. Labor Department said it found a disparity at the Alphabet unit.

"Our annual analysis is extremely scientific and robust," Google says a blog post. A spokesman for the Labor Department told The Wall Street Journal he couldn't comment because the case was ongoing.

On Monday, Department of Labor officials claimed Google, who is a federal contractor, systematically pays female workers less than their male colleagues. The findings came out of a routine compliance probe and the government is suing the Alphabet unit to disclose more compensation information for the investigation.

Google says earnings are based on an employee's role, job level, performance ratings, and location, adding that analysts who determine compensation don't know a worker's gender. What's more, the pay-equity model also factors in workers in the same job categories and analyzes the wages to make sure there is no major difference between genders. Google says it performed that analysis across 52 jobs categories last year and found no pay gap.

Silicon Valley firms has increasingly been under fire for wage disparities and lack of diversity in hiring. While these issues are coming to the forefront for some companies, others are trying to fight the gap: Salesforce invested $6 million in the last two years to adjust the gender pay gap that impacts 11 percent of the company's 25,000 employees.