Members predict on the basis of guess work only which depends on past experiences, data mining / trends etc. Please refer the disclaimers of the site and PNR section for more understanding:
Site | "This website has NO affiliation with the Government-run site of Indian Railways.This site does NOT claim 100% accuracy of fast-changing rail information. You are responsible for independently confirming the validity of information through other sources. "
PNR section | "This is ONLY a Prediction. Predictions can go wrong. Please understand that the final decision and responsibility is yours"