Quantitative and Mixed Research Designs

Quantitative and Mixed Research Designs V. Darleen Opfer

Design Task A principal/head teacher wants to know whether the provision of professional development will improve the instructional practices of teachers. Design a study for answering her question. In your design, address the following questions: What is the unit of analysis? (Will you focus your study on individual teachers, on subject area, on year levels, on the school as a whole?) What is the design chosen for the study? How will you collect your data? What are your variables? (What are will you be measuring?)

Conditions for Establishing Cause-Effect Relationships: • Covariation • Temporal Precedence • No Plausible Alternative Explanations

History Testing Instrumentation Regression Mortality Maturation Selection Selection by maturation interaction Ambiguity about causal direction Diffusion of treatments Compensatory equalization of treatments Compensatory rivalry Types of Alternative Explanations

Ways to Minimize Threats to Validity: • By argument • By measurement or observation • By analysis • By preventive action • By design

Basic Design Elements • Time • Program(s) or Treatment (s) = X • Observation(s) or Measure(s) = O • Groups or Individuals = R = Randomly assigned groups

An Example:

Expanding a Design:X O • Expanding across time O O X O O X O O X O • Expanding across programs O X1 O O X2 O • Expanding across observations O1O2 X O1O2 • Expanding across groups R O X O R O O N O O ______________________________ R O X O R O O N O O

An Expanded Example • The cause-effect relationship X O • The comparison on achievement O X O O O • The expanded design C O X O R O X O R O O C O O

A Strategy for Design Construction • Depict the hypothesized causal relationship • Identify the possible alternative explanation threats • Over-expand the basic design by expanding across time, program observations, and groups accounting for as many alternative explanations as possible • Scale back the design to a manageable plan by considering the effect of eliminating each design component

Mixed Designs • Mixed Model Research • Within-stage mixed model research • Across-stage mixed model research

Mixed Designs • Mixed Method Research

The Nature of Good Design • Theory-Grounded • Situational • Feasible • Redundant • Efficient

Design Task A principal/head teacher wants to know whether the provision of professional development will improve the instructional practices of teachers. Design a study for answering her question. Reconsider your design, address the following questions: What are your variables? (What are will you be measuring?) If you’ve used a mixed method design, is it mixed model or mixed method? Concurrent or sequential? What are potential validity/alternative explanation issues with this study? What are the validity issues accounted for in your approach? And how would you minimize those not accounted for in the design?

Quantitative and Mixed Research Designs