To be fair to the original poster, in Australia, whether you tell every new hire or not, they are still on probation legally in terms of employer obligations, so it is good to tell if you want to establish clarity, and follow appropriate procedures in terms of setting goals and keeping them up to date as end of probation nears to avoid vagueness and stress. Depending on size of hiring organisation, probation is 6 months for big organisations and 12 months for smaller ones.