Centralizing demand information is typically the most effective technique for controlling variability of demand in a supply chain. By centralizing demand information, all parties in the supply chain have access to the same data and can make informed decisions based on accurate and up-to-date information. This helps to reduce the bullwhip effect, where small fluctuations in demand at the consumer level cause larger and larger fluctuations upstream in the supply chain. While holding consignment inventory or additional stock can buffer against variability, they do not address the root cause of demand variability. Closer monitoring of product promotions can help, but it is more of a reactive measure compared to the proactive strategy of centralizing demand information.