•Activity Performance Risk is a key input to operational planning decisions.•A generic list of activity factors is proposed based on major accident theories.•The list provides an overview of factors that determine risk involved in activity.•The list can also facilitate accident investigation on operational level. Operational Planning Decisions, which are characterized by short planning time and high frequency in the operational phase, has received little attention in risk and safety research in oil and gas industry. Activity performance risk, as an important part of the input to such decisions, must reflect explicitly the critical factors (Safety Critical Parameters) that determine the risk level involved in the activity. The paper looks into major accident theories that are relevant for the operational phase to find key concepts and implications for activity performance risk analysis. A generic list of Safety Critical Parameters is developed to assist managing both identified and unidentified risk in the activity. The main conclusion is that the different theories are not conflicting but supplementing to get the list that covers the most important factors in a broad sense. This list provides a guide to Operational Planning Decision makers to collect systematically activity-related risk information to ensure a safe activity.