An invention is regarded as new or novel if it is not anticipated by prior art. Prior art means all those things that has been disclosed to the public, anywhere in the world, by written publication, by oral disclosure, by electrical or any other way, prior to the date of filing. The normal procedure to determine prior art is to do a search but because we cannot do a complete search, therefor what is found will form a rough guide as to whether an idea is new or not.
Different countries like the US, EU and Asian does have different interpretations tough. The US observe a twelve month grace period before the filing date. In EU and Asian countries, there is normally no grace period. The EU thus has an exception in that if the disclosure was made without your consent, and if you can prove it, then you will have a grace period of six months before filing. As for Japan, grace period is normally not allowed but an exception was given recently as a grace period of six months was allowed. A novelty grace period of twelve (12) months preceding the filing date of the Malaysian application is available for prior disclosure if such disclosure was not by the applicant, or due to the abuse of the rights of the applicant (or his predecessor).
Novelty of an invention is assessed relative to existing prior art and the standard method used for this purpose is by way of a prior art search. Prior Art search is normally done to determine whether an idea is patentable or not. But we cannot say for sure that the idea is patentable even if we did not find any prior art as we cannot do a complete search. And even if a patent has been granted, it does not mean that it could not be invalidated, so when we do a prior art search, we can only get a rough idea as to whether that idea is novel or not.