TCS Corporation has recently decided to manufacture a product in its own facilities rather than outsource to Asian manufacturers. Its new plant will last about ten years. TCS is considering two options: build a large plant now that will have sufficient capacity to handle demand into the foreseeable future, or build a small plant that can be expanded two years later, after demand is better known. TCS will not expand the small plant unless demand in the first two years exceeds a threshold level.

TCS assumes that the level of demand in subsequent years will be the same as in the first two years (e.g., if demand is high in the first two years, it will continue to be high in the next eight years). What additional data are needed to determine the optimal decision?