Vaccination: 1. giving a person or an animal a vaccine, especially by injecting it, in order to protect them against an infectious disease; 2. inoculation with vaccinia virus against small-pox. szczepienie ochronne

Vaccine: substance containing live, modified or killed infectious organism or its toxin which is administered to susceptible individuals to protect them from the disease in question. szczepionka

Vadose zone: zone between land surface and the water table within which the moisture content is less than saturation (except in the capillary fringe) and pressure is less than atmospheric. strefa aeracji

Valid: 1. well-based or logical (argument); trafny 2. legally binding or acceptable. prawomocny, ważny

Validation: process of establishing that a method is sound. uzasadnienie, walidacja

Validity: 1. extent to which a technique measures what it is intended to measure; cf. construct validity, convergent validity. 2. extent to which researcher's findings reflect the purpose of the study while observing the principle of integrity. trafność

Validity measurement: expression of the degree to which a measurement measures what it purports to measure. pomiar trafności

Validity, study: degree to which the inference drawn from a study, especially generalizations extending beyond the study sample, are warranted when account is taken of the study methods, the representativeness of the study sample, and the nature of population from which it is drawn; badanie trafnościinternal validity: index and comparison groups are selected and compared in such a manner that that the observed differences between them on the dependent variables under study may, apart from sampling error, be attributed only to the hypothesized effect under investigation; trafność wewnętrzna, external validity: study is externally valid or generalisable if it can produce unbiased inferences regarding a target population.