To best evaluate, from a financial standpoint, an IT investment whose benefits cannot be firmly established in advance, you would use:

The real option pricing model is particularly well-suited for evaluating IT investments with uncertain benefits because it incorporates the flexibility and strategic value of investment decisions that can be adjusted as new information becomes available. This model allows decision-makers to account for the potential future options that an investment may provide—such as the ability to expand, defer, or abandon a project—depending on the evolving circumstances and outcomes.

In situations where the benefits of an investment cannot be firmly established, the real options approach enables businesses to quantify the value of future opportunities and risks. It essentially reduces the risk associated with uncertainty by recognizing that decisions can be revisited over time, which is particularly relevant in the dynamic field of IT.

This model contrasts with traditional financial evaluation methods, which may not adequately capture the complexities and uncertainties inherent in IT investments. Other methods mentioned may focus on different aspects of investment analysis, but they wouldn't fully account for the value of flexibility in uncertain environments, which makes real option pricing the appropriate choice in this context.