How do executives and managers make decisions in practice — what are the main decision-making approaches/styles, and how should each be selected depending on the situation?

Note: Focus on (1) characterizing the major approaches and (2) practical situational selection ("which approach when"). Cover established theory and real-world managerial practice, including small-business owner-managers. NOT about: the biography of any single theorist, voting/social-choice math, or automated/algorithmic decision systems.

Context

We want a practical, well-sourced survey of how business leaders actually decide, plus a usable framework for choosing the right approach by situation. The audience is a solo founder / small-business context aiming to understand and improve real-world decision-making — not an academic literature review.

Scope:

  • Business/organizational decisions by executives and managers (strategic and operational), including owner-managers of small companies.
  • Cover the principal recognized approaches/styles (e.g., rational/analytic, bounded-rationality/satisficing, expert intuition, incremental, data/evidence- driven, and group/political), characterized rather than merely listed.
  • Emphasize situational fit: how the right approach depends on uncertainty, time pressure, stakes, reversibility, goal clarity, and data availability.
  • Decision point: deliver a selection framework an executive can use to pick an approach per situation, plus the practical steps and common pitfalls of each.

Limit analysis to the ~6 most important approaches; do not enumerate more than 6.

Questions

  1. Principal approaches: What are the main decision-making approaches/styles executives use? For each, give the core idea, key assumptions, typical process/steps, strengths, and limitations. Include both classic models and contemporary practice (data-driven, expert intuition).

  2. Situational selection ("使い分け"): Under what conditions is each approach most appropriate or inappropriate? Map approaches to situational variables (uncertainty, time pressure, stakes, reversibility, goal clarity, data availability, individual vs group). Provide a decision matrix.

  3. Process and pitfalls: What concrete steps do effective executives follow, and which cognitive biases / failure patterns most degrade executive decisions — with practical mitigations?

  4. Group dimension (brief): How does decision-making differ for group/board settings vs individuals (participation, consensus, escalation)?

Output

Provide a structured report:

  • Executive summary (3-5 key findings)
  • Per-question analysis with specific examples
  • A decision matrix: approach × situational fit (when to use / when to avoid)
  • A concise step-by-step "how to choose an approach" checklist
  • References with URLs (cite international and, where available, Japanese sources)

Write the final report in Japanese (日本語). Use markdown tables and inline citations with URLs.