Advantage factor is a representation of the relative advantage each side has during a planetary invasion. The base advantage factor is modified by several conditions, including quality of the soldiers, their courage, planetary defenses, and technology level. The invading force gets a 5 point advantage due to air superiority. The invading force can choose their preferred invasion tactic, which also may affect the advantage factor. Once a tactic has been selected, the potential advantage factors for both sides are displayed. The values fluctuate throughout their range until the "Attack" button is selected to start combat. Once combat has begun the advantage factors lock in at whatever value was displayed when the button is pressed, and these are the advantage factors that will be applied to the entire battle. This means that it is possible for a theoretically superior force to be at a disadvantage if the values are locked in at the wrong time.