Which of the following is NOT a published source of external strategic information?

The correct choice emphasizes that periodicals, while they provide valuable information, are usually not classified as a distinct source of external strategic information when compared to journals, reports, and directories.

Journals are peer-reviewed publications that present research and studies relevant to strategic management, offering in-depth discussions and analyses on various topics. Reports, often produced by organizations and research firms, summarize findings, trends, and data analyses that are crucial for strategic decision-making. Directories serve as lists or databases of companies, people, or resources in specific fields, serving as reference tools for strategic insights.

Periodicals, on the other hand, can encompass a wide range of publications that might not be as rigorously curated as journals or specific as reports. They can include newspapers or magazines that may provide news or general articles, which might not always focus on the strategic aspects necessary for informed decision-making in a business context. This distinction helps to clarify the role each type of publication plays in gathering strategic information.