The article looks at how seniority affects wages in companies. By analyzing data from multiple observations within firms, the researchers found that seniority does impact wages within a company. However, this doesn't necessarily mean that more experience equals higher pay due to on-the-job training requirements. Employees with specific training needs may not see as much of a wage increase over time. Additionally, workers paid based on their output may not see much of a pay increase as they gain more experience.