Baseline purchase probability
The baseline purchase probability for focused visits will be high relative to the visit effect. The purchasing effect is likely to be low if negative, and high if positive.
If someone has had a negative purchasing experience from your site, they are simply less likely to visit the site again at all. If they do make a focused visit to your site after a negative purchase experience, that experience wasn't very important to them, and the importance of that negative experience is relatively low.
By contrast, research visitors will have low baseline purchase probabilities and purchase effects, but the visit effect will be high. Browsing visitors have similarly low baseline purchase probabilities, while the visit effect can vary strongly from visit to visit and thus result in some occasional impulse buying.
