To add to what Seng Kiat wrote:
In contemplating Paticca Samuppada backwards (“patiloma”), one starts by replacing, “jati paccaya jara, marana,…” with “jati rirodha jara, marana..nirodha”.
Then, “bhava paccaya jati” is replaced by “bhava nirodha jati nirodha”, etc.
Then one can see some key insights.
For example, if one does not do “apunna abhisankhara”, no corresponding “bad vinnana” would arise that can lead to births in the apayas.
So, it is not just repeating words. One needs to “see” how bad births can be stopped from arising by stopping corresponding abhi sankhara. Of course, as one forcefully stops such abhi sankhara, one’s “bad gati” would reduce over time.
– However, it is also essential to learn Dhamma to get rid of avijja, the root cause.