internal validity is hard to explain but i will try. when i say poverty causes beggary. I am creating a relationship beween idependent variable(poverty) and dependent variable(beggary). this is also a causal relaionship as poverty causes beggary. now interal validity is the degree to which this causal relationship is true. the higher the inernal validity, he higher the causal relationship.

however in the case of poverty causes beggary, there is a correlation, i some cases, the beggary may cause poverty because one wholly relies on it and does not do any job etc.

but in case of a scientific exaple like when two atoms of Hydrogen and One atom of Oxygen chemically combined they form water. this causal relationship is very strong with high validity.


now internally validity in the example of water is higher than in the example of poverty.

Hope it was satisfactory