TYPES OF EXPERIMENTAL DESIGN

~INDEPENDENT MEASURES~

→ different participants are used in each condition of the independent variable (done by random allocation, so each participant has an equal chance of being assigned to a certain group)

+ Strengths

• no issue with order effects and demand characteristics (compared to repeated measures)

- Limitations

• subject to being affected by participant variables

• less economical and more time-consuming, as you need 2X the number of participants (compared to repeated measures)

~REPEATED MEASURES~

→ the same participants take part in each condition of the independent variable

+ Strengths

• fewer participants are needed (compared to independent measures), so it’s more economical

- Limitations

• subject to demand characteristics as some participants may try to work out the aim of the study

• subject to order effects

~MATCHED PAIRS~

→ each condition uses different participants but effort is made to match the participants in each condition in terms of key characteristics which may affect their performance

+ Strengths

• low risk of demand characteristics and order effects

- Limitations

• matching participants requires pre-testing which can be expensive and time-consuming