Chapter 4: Evaluate and Iterate You've learned to structure clear prompts using the TIP framework—defining your Task, providing necessary Information, and specifying your desired Product. That's the foundation. But effective prompt engineers don't expect perfection on the first try—they iterate, just like how we take several photos from different angles before picking the best one. This chapter will teach you how to systematically evaluate outputs and refine your prompts to get consistently better results. Why Outputs Vary: The Probabilistic Nature of LLMs Remember the autocomplete analogy from Chapter 1? LLMs make probabilistic predictions—they don't pick the single "correct" next word, but calculate probabilities for thousands of options and sample from those possibilities. This means even identical prompts might yield slightly different responses. One time an LLM might say "Remote work has revolutionized workplace dynamics," another time ...