A police certificate may or may not have period of validity itself, and criteria for validity varies for each country. Australia, for example, recognizes police certificates for 12 months from their issue dates for both visa and citizenship applications, independent of any validity period noted on the certificates themselves. As in many countries, this practice is neither mandated nor noted in any legislation; rather, the approach has simply been adopted by Australia’s Department of Immigration and Citizenship for the sake of consistency across varying jurisdictions.