Chapter_10_-_Non_and_Quasi_Designs

Chapter_10_-_Non_and_Quasi_Designs - PSYC 310 Chapter 10...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Non- and Quasi-experimental Designs Non- and Quasi-experimental Designs PSYC 310 – Chapter 10 PSYC 310 – Chapter 10
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Experimentation involves the manipulation of an IV and measurement of its effect on the DV. Sometimes, however, the researcher is not able to manipulate an IV and must therefore work with pre-existing levels of the IV. In both non- and quasi-experimental designs, there is no manipulation of the IV - researchers compare pre-existing groups on a DV of interest.
Background image of page 2
Typically, the IV is a participant variable (e.g., age, marital status) or a time variable (e.g., pre- or post- an event). Group 1 Group 2 Public H.S. Private H. S. IQ
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Both designs are similar in that there is no manipulation of the IV – where they differ is in whether there is an attempt to control for threats to internal validity. Non-experimental: no attempt to control for threats to internal validity. Quasi-experimental: an attempt is made to control for threats to internal validity.
Background image of page 4
Between groups: For both, there is no random assignment to groups – you must use pre-existing groups. Thus, you end up with non-equivalent groups and this raises the problem of assignment bias. Your groups may differ on a variable other than your IV and this can be a possible confound in your study.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
What other differences are there in these groups aside from IQ? Group 1 Group 2 Public H.S. Private H. S. IQ
Background image of page 6
Between groups: Because of this lack of control, there is a threat to internal validity. There are 3 types of non-equivalent group designs; 1 & 2 are non-experimental and 3 is quasi-experimental. 1. Differential design N 2. Post-test only NECG design N nonequivalent control group 3. Pre-test/post-test NECG design Q
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Between Groups Designs 1. Differential design N Also called an ex post facto (after the fact) design – simplest of the 3 BG designs. Simply compare pre-existing groups to find a
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 35

Chapter_10_-_Non_and_Quasi_Designs - PSYC 310 Chapter 10...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online