Quantitative and Mixed Research Designs V Darleen Opfer

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: n. 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? ) n. What is the design chosen for the study? How will you collect your data? n. What are your variables? (What are will you be measuring? )

Conditions for Establishing Cause. Effect Relationships: n Covariation n Temporal Precedence n No Plausible Alternative Explanations

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

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

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

An Example: R O X O O

Expanding a Design: X O n Expanding across time n Expanding across programs O O X 1 O O X 2 O Expanding across observations O 1 O 2 X O 1 O 2 n Expanding across groups R O X O R O O N O O _______________ R O X O R O O N O O n

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

A Strategy for Design Construction n n 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 n Mixed Model Research – Within-stage mixed model research – Across-stage mixed model research

Mixed Designs n Mixed Method Research

The Nature of Good Design n Theory-Grounded n Situational n Feasible n Redundant n 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: n. What are your variables? (What are will you be measuring? ) n. If you’ve used a mixed method design, is it mixed model or mixed method? Concurrent or sequential? n. What are potential validity/alternative explanation issues with this study? n. What are the validity issues accounted for in your approach? And how would you minimize those not accounted for in the design?