Sampling techniques

Sampling techniques

1. RANDOM

   • Pick names out of hat or though a computer. Everyone has an EQUAL CHANCE
     • Advantages: Quick & easy & everyone has an equal chance
     • Disadvantages: Requires up to date sampling frame & can be unrepresentative

2. QUOTA

   • Researcher is told how many respondants of a certain type are required
     • Advantages: Researcher can control variables without a sampling frame & it's quick and cheap
     • Disadvantages: Not random & pps may be put off by reasearcher asking personal questions e.g. age

3. STRATIFIED

   • Split sample into groups & then ]select randomly from groups (groups must be in same proportion as target population)
     • Advantages: Researcher can control variables important to research & increased precision
     • Disadvantages: Complex and time consuming & often impractical as sampling frame doesn't always contain info required

4. SNOWBALL

   • Uses personal contacts to build up sample
     • Advantages: No sampling frame needed & can allow access to sensitive and secretive groups
     • Disadvantages: May run out of pps & not representative as pps are part of a network

5. CONVENIENCE/OPPORTUNITY

   • Selecting those conveniently available to the researcher
     • Advantages:Quick, cheap and easy & no sampling frame needed
     • Disadvantages: Sample is not representative & bias