Evidence Tetris in the Pixelated World of Validity Threats

Valid empirical studies build confidence in scientific findings. Fortunately, it is now common for software engineering researchers to consider threats to validity when designing their studies and to discuss them as part of their publication. Yet, in complex experiments with human participants, there is often an overwhelming number of intuitively plausible threats to validity -- more than a researcher can feasibly cover. Therefore, prioritizing potential threats to validity becomes crucial. We suggest moving away from relying solely on intuition for prioritizing validity threats, and propose that evidence on the actual impact of suspected threats to validity should complement intuition.