The study found that changes in outside job options can affect wages in continuing jobs. By analyzing a crafts reform in Germany, researchers discovered that employees in deregulated crafts saw smaller wage increases compared to those in non-reformed crafts. This wage difference was driven by employees renegotiating their wages, not employers. Factors like works councils, firm size, and regional unemployment did not impact wage differentiation. The study used a large dataset to ensure fair comparisons between different groups of employees.