What if Subjects Can't be Randomly Assigned?

1977 ◽  
Vol 19 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Russell S. Vaught
Keyword(s):  
Monte Carlo ◽  
Experimental Design ◽  
Treatment Effects ◽  
Experimental Designs ◽  
Random Assignment ◽  
Monte Carlo Studies ◽  
Quasi Experimental ◽  
Unbiased Estimates ◽  
Evaluative Research ◽  
Biased Estimates

Random assignment to treatment is not always possible in evaluative research. The semi-experimental design discussed here has aspects of both full experimental and quasi-experimental designs. Monte Carlo studies are used to explore and exemplify the strengths and weaknesses of the design. The analysis suggested is found to give unbiased estimates of treatment effects and error mean squares but biased estimates of assignment effects. Some further aspects of the design and its use are discussed.

scholarly journals Speculations on Quasi-Experimental Design in HIV/AIDS Prevention Research

2012 ◽  
Vol 3 (1) ◽  
pp. 52
Author(s):  
Donald T. Campbell ◽  
Beatrice J. Krauss
Keyword(s):  
Experimental Design ◽  
Hiv Prevention ◽  
Research Design ◽  
Research Community ◽  
Experimental Designs ◽  
Prevention Research ◽  
Quasi Experimental ◽  
Aids Research ◽  
Speculative Discussion ◽  
Hiv Aids

This paper provides a speculative discussion on what quasi-experimental designs might be useful in various aspects of HIV/AIDS research. The first author’s expertise is in research design, not HIV, while the second author has been active in HIV prevention research. It is hoped that it may help the HIV/AIDS research community in discovering and inventing an expanded range of possibilities for valid causal inference. DOI:10.2458/azu_jmmss_v3i1_campbell

Designing Experiments

2015 ◽  
pp. 82-96
Keyword(s):  
Experimental Design ◽  
Internal Validity ◽  
Random Selection ◽  
Experimental Designs ◽  
Control Groups ◽  
Test Measurement ◽  
Post Test ◽  
Quasi Experimental ◽  
And Control

In this chapter, students will learn the process of designing experiments. The classic experimental design is presented first. Following this, three distinct quasi-experimental designs are presented. The benefits and burdens of the classic and quasi-experimental designs are discussed in depth. By the end of this chapter, students will understand concepts related to random selection, generalizability, treatment and control groups, pre- and post-test measurement of the dependent variable, and internal validity.

scholarly journals Measuring the Impacts of Teachers I: Evaluating Bias in Teacher Value-Added Estimates

2014 ◽  
Vol 104 (9) ◽  
pp. 2593-2632 ◽  
Author(s):  
Raj Chetty ◽  
John N. Friedman ◽  
Jonah E. Rockoff
Keyword(s):  
Student Achievement ◽  
School District ◽  
Experimental Design ◽  
Test Scores ◽  
Value Added ◽  
Good Measure ◽  
Teaching Staff ◽  
Quasi Experimental ◽  
Unbiased Estimates ◽  
Parent Characteristics

Are teachers' impacts on students' test scores (value-added) a good measure of their quality? One reason this question has sparked debate is disagreement about whether value-added (VA) measures provide unbiased estimates of teachers' causal impacts on student achievement. We test for bias in VA using previously unobserved parent characteristics and a quasi-experimental design based on changes in teaching staff. Using school district and tax records for more than one million children, we find that VA models which control for a student's prior test scores provide unbiased forecasts of teachers' impacts on student achievement. (JEL H75, I21, J24, J45)

Deliberation and Experimental Design

2018 ◽  
pp. 662-677
Author(s):  
Kevin Esterling
Keyword(s):  
Experimental Design ◽  
Causal Inference ◽  
Observational Data ◽  
Research Design ◽  
Causal Effect ◽  
Internal Validity ◽  
Experimental Designs ◽  
Quasi Experimental ◽  
Methodological Considerations

This chapter describes the methodological considerations necessary for making a causal inference regarding the effect of institutions and group contexts on deliberation. This chapter focuses on the elements of the research design of a study and the assumptions that are necessary to state a causal inference given a particular design; these considerations are applicable to randomized experimental designs, both in the lab and in the field, as well as to quasi-experimental or natural experimental designs using observational data. The chapter shows how to assess the internal validity of a study for identifying a causal effect for a given study and briefly discusses external and epistemic validity considerations that are of particular urgency for empirical deliberation.

A Research Strategy for Evaluating the Effectiveness of Psychotherapy

1975 ◽  
Vol 37 (3) ◽  
pp. 1011-1021
Author(s):  
Steven J. Gross ◽  
Jeffrey O. Miller
Keyword(s):  
Experimental Design ◽  
Therapeutic Intervention ◽  
Classification Scheme ◽  
Research Strategy ◽  
Outcome Studies ◽  
Experimental Designs ◽  
Alternative Formulation ◽  
Random Assignment

A classification scheme is proposed that integrates previous outcome studies in psychotherapy. Studies are classified into one of three frameworks according to the question addressed, the assumptions made, and the experimental designs used. Strengths and weaknesses of the three frameworks are examined within the context of specific studies of outcome. Evidence from the three frameworks suggests an alternative formulation of the question about outcome and a new experimental design. Specifically, the design involves evaluating the effectiveness of psychotherapy with respect to a population of patients deemed appropriate for psychotherapy. This design avoids random assignment of patient to psychotherapist and permits the investigator to address the question of whether psychotherapists are effective with patients whom they regard as appropriate for their particular type of therapeutic intervention.

scholarly journals Teknik Sinema Edukasi untuk Meningkatkan Empati pada Siswa SMP Pelaku Perundungan

2020 ◽  
Vol 4 (1) ◽  
pp. 39-48
Author(s):  
Amallia Putri Kartika Sari ◽  
Nanik Prihartanti ◽  
Zahrotul Uyun
Keyword(s):  
Experimental Design ◽  
Control Group ◽  
Random Assignment ◽  
Control Group Design ◽  
Group Design ◽  
Quasi Experimental

Teknik Sinema Edukasi ini bertujuan untuk menguji pengaruh pelatihan teknik sinema edukasi efektif untuk menungkatkan empati pada siswa SMP pelaku perundungan. Keseluruhan subjek dalam penelitian berjumlah 30 siswa yang memiliki empati rendah dengan rerata usia 13-14 tahun, dibagi dalam 2 kelompok yaitu eksperimen dan kontrol. Keduanya tidak dikelompokkan secara acak (non random assignment). Metode pengumpulan data menggunakan skala empati dengan validitas sebesar 0,80 dengan p=0,040 dan reliabilitas 0,891. Penelitian ini menggunakan metode Quasi Experimental Design dengan desain pretest-postest control group design. Uji hipotesis menggunakan Man Whitney U-Test dengan nilai z= -4.706, nilai Asymp. Sig. (2-tailed) 0, 813 (p>0.05) yang artinya terdapat perbedaan tingkat empati yang signifikan antara kelompok eksperimen dan kelompok kontrol setelah diberikan pelatihan teknik sinema edukasi. Hal tersebut sesuai dengan hipotesis pada penelitian ini yakni pelatihan teknik sinema edukasi efektif meningkatkan empati pada siswaSMP pelaku perundungan. Ada 4 sesi dalam pelatihan ini yang berpengaruh dalam peningkatan empati pada peserta intervensi yakni “bagaimana empatiku, mendalami empati, strategi penyelesaian konflik dan rencana tindakan”. Sesi tersebut mewakili aspek-aspek yang ada dalam empati.

scholarly journals Speculations on Quasi-Experimental Design in HIV/AIDS Prevention Research

2012 ◽  
Vol 3 (1) ◽  
pp. 52
Author(s):  
Donald T. Campbell ◽  
Beatrice J. Krauss
Keyword(s):  
Experimental Design ◽  
Hiv Prevention ◽  
Research Design ◽  
Research Community ◽  
Experimental Designs ◽  
Prevention Research ◽  
Quasi Experimental ◽  
Aids Research ◽  
Speculative Discussion ◽  
Hiv Aids

This paper provides a speculative discussion on what quasi-experimental designs might be useful in various aspects of HIV/AIDS research. The first author’s expertise is in research design, not HIV, while the second author has been active in HIV prevention research. It is hoped that it may help the HIV/AIDS research community in discovering and inventing an expanded range of possibilities for valid causal inference. DOI:10.2458/azu_jmmss_v3i1_campbell

scholarly journals Transformative Treatments

2016 ◽  
Author(s):  
L.A. Paul ◽  
Kieran Healy
Keyword(s):  
Experimental Design ◽  
Gold Standard ◽  
Experimental Designs ◽  
Selection Effects ◽  
Theoretical Interest ◽  
Causal Pathways ◽  
Quasi Experimental ◽  
Social Scientific Research ◽  
Social Scientific ◽  
And Control

Contemporary social-scientific research seeks to identify specific causal mechanisms for outcomes of theoretical interest. Experiments that randomize populations to treatment and control conditions are the “gold standard” for causal inference. We identify, describe, and analyze the problem posed by *transformative treatments*. Such treatments radically change treated individuals in a way that creates a mismatch in populations, but this mismatch is not empirically detectable at the level of counterfactual dependence. In such cases, the identification of causal pathways is underdetermined in a previously unrecognized way. Moreover, if the treatment is indeed transformative it breaks the inferential structure of the experimental design. Transformative treatments are not curiosities or “corner cases”, but are plausible mechanisms in a large class of events of theoretical interest, particularly ones where deliberate randomization is impractical and quasi-experimental designs are sought instead. They cast long-running debates about treatment and selection effects in a new light, and raise new methodological challenges.

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