The rise and fall of the sliding scale, or why wages are no longer indexed to product prices

Though almost no postwar union contracts indexed wage rates to prices of the employer's products, union agreements linking wage rates to product prices, known as sliding scales, were common in some industries in the United States and Britain from the 1860s through the 1930s. This paper explains why sliding scales disappeared after the 1930s, and examines what practical experience with sliding scales revealed about fundamental constraints on wage indexation. Paradoxically, the history of sliding scales confirms that workers' information about product prices and materials costs is generally imperfect, in ways that would substantially constrain wage indexation in long-term contracts. Sliding scales were not indexed long-term contracts, but rather devices to forestall costly strikes in the absence of contracts by revealing employers' private information about product demand. In the postwar US, unions and employers failed to link wage rates to product prices because they had gained the ability to enter binding contracts, which could achieve the benefits of preventing strikes without incurring the extra negotiation costs and information problems associated with product-price indexation. I present a model to show how sliding scales could forestall strikes by revealing information, and how the introduction of binding union contracts reduced incentives to link wages to product prices.