1 / 6

Research Methods

Research Methods. Chapter 6 Causation & Experimental Design. Three Criteria For Determining Causation in a Hypothesis. Correlation (association) Time Order Non-Spuriousness Two additional things used to strengthen a causal statement Identify Causal Mechanism Specify the context.

eldon
Download Presentation

Research Methods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Research Methods Chapter 6 Causation & Experimental Design

  2. Three Criteria For Determining Causation in a Hypothesis • Correlation (association) • Time Order • Non-Spuriousness Two additional things used to strengthen a causal statement • Identify Causal Mechanism • Specify the context

  3. Why Experiment?: True Experiments • True experiments must: • have at least 2 comparison groups • Experimental Group • Control Group • have variation in the Ind. Variable before assessment of the dependent variable • Have subjects randomly assigned to 2 or more groups • Ensures internal validity but not generalizability • Sometimes matching is used as a poor substitute for random assignment

  4. Exp. Are well suited to produce valid conclusions about causality Less well suited to achieve generalizability Validity in Experiments

  5. Let’s take a look at some of the ways in which experiments help (or don’t help) to resolve potential problems with causal (internal) validity and generalizability…

  6. What Are The Threats to Validity in Experiments? • Threats to causal (internal) validity • Non-comparable groups • When the experimental group and control group are not really comparable • Endogenous change • When natural developments in the subjects account for changes between pre and post tests • History • When subjects become aware of things outside the experiment (like the news) that affects their outcome scores • Contamination • When comparison and treatment groups somehow affect one another • Treatment Misidentification • When subjects experience a treatment that was unintended • Generalizability (The Achilles heel of true experiments….) • Sample Generalizability • Cross-Population Generalizability • Interaction of Testing and Treatment

More Related