Which measure would likely not indicate the effectiveness of an organization's IT investment decisions?

Historical financial statements typically provide insights into an organization's past performance, profitability, and financial health but do not directly measure the effectiveness of IT investment decisions. They summarize overall financial outcomes rather than specifically linking them to IT initiatives or technological advancements, making them less relevant for assessing the immediate impact or success of IT investments.

In contrast, factors like IT organizational structure can show how well IT resources are aligned with business goals, data accuracy assessments reflect the quality and reliability of data systems which are often a direct result of IT investments, and customer satisfaction scores can indicate how effectively IT initiatives enhance the customer experience and service delivery. Therefore, historical financial statements stand out as the least effective measure for evaluating IT investment efficacy in the current context.