Definition: Non-probability sampling
The selection of a sample of producers and products is non-random but based on expert knowledge of judgment. Non-probability sampling is also known as "non-random sampling", "purposive sampling" and "judgmental sampling" ("Eurostat-OECD Methodological Guide for Developing Producer Price Indices for Services").
The deliberate, i.e. non-random, selection of a sample of outlets and products on the basis of the knowledge or judgement of the person responsible. Also known as purposive sampling and judgemental sampling ("Consumer Price Index Manual: Theory and Practice").
Eurostat, Organization for Economic Cooperation and Development (OECD), "Eurostat-OECD Methodological Guide for Developing Producer Price Indices for Services (Second Edition)", Luxembourg, Paris, 2014