Rebirth and Karma

Most people seem to think that rebirth (Buddhists prefer "rebirth" over "reincarnation") is due to karma. Following is what H.H. The Dalai Lama says about the subjects:

"From the Buddhist point of view, the theory of rebirth is not explained in terms of the concept of karma. The theory of rebirth should be understood on the basis of our understanding of the nature of causality, because according to Buddhism, every event must have preceding causes and conditions. Therefore, even a single cognitive event - say an instance of consciousness or mind - must have causes and conditions; and so through this process we can trace the beginningless continuum to the consciousness. And once we are able to develop that kind of understanding of the causal process, then the theory of rebirth develops naturally on the basis of that kind of causal understanding.

Now where does karma fit in relation to the theory of rebirth? It determines the kind of rebirth an individual may have. Good karma results in a favorable rebirth, and negative karma results in an unfavorable one. Of course, we must understand that when we are talking of karma, we are talking about an instance of the causal process; karma is part of that process. When we speak of karma we are referring not just to an event but rather, an event which involves an agent, a doer, an act. Karma is an act committed by an agent, a being with motivation, determining the cause of that process."

Note "the theory of rebirth is not explained in terms of the concept of karma" and "(karma) determines the kind of rebirth an individual may have."

To my understanding the "causes and conditions," or specifically, "conditions" can be explained as the pratityasamutpada.