COMMENTS

  1. Do experiments always need a control group?

    A true experiment always includes at least one control group that doesn't receive the experimental treatment. However, some experiments use a within-subjects design to test treatments without a control group. For strong internal validity, it's usually best to include a control group if possible.

  2. Quasi-Experimental Design

    Quasi-experimental design is a research method that aims to establish a cause-and-effect relationship without random assignment. Learn the differences, types, advantages and disadvantages of quasi-experiments compared to true experiments.

  3. Doing research without a control group

    What is a control group? When we do experimental research, it is common practice to divide our sample into two groups. One group (the 'intervention' or 'experimental' group) is the people on whom we test whatever new idea or method we want to measure.The other group, or control group, usually goes about doing whatever they did, except that we get to test them in the same ways as the ...

  4. Do experiments always require a control group?

    A true experiment always includes at least one control group that doesn't receive the experimental treatment. However, some experiments use a within-subjects design to test treatments without a control group. Learn more about the pros and cons of each design.

  5. Control Group Vs Experimental Group In Science

    A control group is a group of participants who do not receive the treatment or manipulation of the independent variable under investigation. An experimental group is a group of participants who do receive the treatment or manipulation of the independent variable. Learn the differences, purposes, and types of control groups in scientific research.

  6. PDF The Methods for the Synthesis of Studies without Control Groups

    1. Incorporate studies without control groups into systematic reviews, especially when there are no other studies to consider. Studies without control groups can also pro-vide information on long-term effectiveness, rare events and adverse effects. 2. Do not generalize the direction of differences in outcome between randomized and

  7. Quasi-Experimental Research Design

    Quasi-experimental design is a research method that evaluates causal relationships without full control over the independent variable. Learn about the types, methods, steps, examples, and applications of quasi-experimental design.

  8. Quasi-Experimental Design

    It differs from experimental research because either there is no control group, no random selection, no random assignment, and/or no active manipulation. " This type of research is often performed in cases where a control group cannot be created or random selection cannot be performed. This is often the case in certain medical and psychological ...

  9. Research without Control Groups

    In field research, experimental and control groups are more likely to differ systematically on important dimensions other than independent variables. ... describes a research design that has the potential for providing unbiased estimates of impact without use of a control group, and (3) illustrates the use of the design with a study of a ...

  10. Control Groups and Treatment Groups

    A true experiment (a.k.a. a controlled experiment) always includes at least one control group that doesn't receive the experimental treatment.. However, some experiments use a within-subjects design to test treatments without a control group. In these designs, you usually compare one group's outcomes before and after a treatment (instead of comparing outcomes between different groups).

  11. PDF Checklist for Quasi-experimental Studies (Non-randomized Experimental

    studies without an independent control group. Check if there are independent, separate groups, used as control groups in the study. [Note: The control group should be an independent, separate control group, not the pre-test group in a single group pre-test post-test design.] 5. Were there multiple measurements of the outcome both pre and post the

  12. When is not necessary to use a control group in an experimental

    There are a lot of instances when a control group is not included in an experimental design. Prospective cohort studies are one, in which a group of individuals are tracked longitudinally.

  13. Opportunities and challenges in using studies without a control group

    Because these studies are "missing" a direct, concurrent comparison group, they are typically deemed non-informative on comparative effectiveness. However, in principle, single group studies can provide information on causal treatment effects by extrapolating expected outcomes in the "missing" untreated arm.

  14. 8.2 Non-Equivalent Groups Designs

    Learn about different types of nonequivalent groups designs, such as posttest only, pretest-posttest, and interrupted time-series, and their threats to internal validity. See examples of how to improve these designs by adding a pretest, a control group, or a switching replication.

  15. PDF Research without Control Groups

    cause experimental versus control group comparisons to be biased. The classic New Jersey Negative Income Tax Study found attrition varied from 8% in the "best" experimental group to 25% in the control group. Nonequivalence in field settings also occurs because of a shift from the individual to larger units of intervention.

  16. Non-Equivalent Groups Designs

    Learn about the different types of nonequivalent groups designs, such as posttest only, pretest-posttest, and interrupted time-series. The pretest-posttest design with nonequivalent groups compares the change in scores from pretest to posttest across treatment and control groups.

  17. Control Groups & Treatment Groups

    A control group is a group that does not receive the treatment or independent variable under study, allowing researchers to compare the effects of the treatment with a baseline or alternative. Learn how control groups are used in experiments, quasi-experiments, and matching designs, and why they are important for internal validity.

  18. No Treatment? No Problem: The Science Behind Control Groups

    Without control groups, we would be left guessing whether the observed outcomes were genuinely a result of the intervention or merely a coincidence. So, the next time you come across an experimental study, remember to check for a control group. It's this silent player that makes the loud proclamation of cause and effect possible in research.

  19. Experimental research

    Learn about the basic concepts, types, and threats of experimental research, a rigorous method of linking cause and effect through treatment manipulation. This chapter covers true experimental designs, such as pre-post designs, and quasi-experimental designs, such as one-group pre-test post-test design.

  20. How to perform a meta-analysis of studies without a control group?

    However, the studies did not used control groups, due to the types of questions used. How can I do the meta-analysis or which software can I use? Briefly my problem is as follows: I reviewed studies which the goal was to evaluate the perception of certain samples of their own behaviour.