Pilot study key terms

Independent groups

a type of experimental design in which participants are allocated to different groups, where each group represents one experimental condition

Experimental group

The group in an independent group design containing the independent variable as distinct from the control. For example, in a drug trial, ppts in the experimental group would receive the drug

Control group

In an independent group design, this is the group that receive no treatment.

Their behaviour acts as a baseline against which the effect of the IV on the experimental group can be measured.

In a drug trial, this is the group that receives a placebo

Placebo

- A fake drug or therapy
- should have no effect on the behaviour being studied. - therefore, it can be used to separate out the effects of the IV from any effects caused merely by receiving any treatment
- many people often report having been recovered or show positive signs of recovery following taking a placebo

Pilot study

* A small scale trial run of an actual investigation which may involve a handful of participants in order to test the procedure runs smoothly


* aim is to allow researcher to make changes if necessary

Blinded study

A type of research design in which a participant is not aware of the research aims and/or which condition of the experiment they are receiving. In a drug trial, this means not knowing whether they are taking the drug or the placebo. This is to reduce the confounding effects of demand characteristics

Demand characteristics

any cue from the researcher or from the research situation that may be interpreted by the participants as revealing the true purpose of the study. This may lead to a participant changing their behaviour within the research situation

Double blind trial

\-A type of research design in which neither the ppt or the researcher knows which condition of the experiment each ppt is receiving.

\-In a drug trial, this means neither ppt or researcher knows which drugs are real and which are placebo.

\-Reduces investigator effects on the research outcome

Research bias

Any effect of the investigator's behaviour (whether conscious or unconscious) on the research outcome

What are the three types of investigation?

* experiment
* self-report (questionnaire/interview)
* observational study

What are the aims of piloting?

* identify any potential issues
* modify the design / procedure
* saving time and money

Single-blind procedure

* ppts will not be told the aims of the study
* other details may also be withheld from ppts such as which condition of the IV they are in

Why is a single-blind procedure conducted?

To control for the confounding effects of demand characteristics. Any information that might create expectations is not revealed until the end

What are control groups used for in experimental studies?

* for comparison


* if the change in behaviour of the experimental group is much greater than the control group, then the researcher can assume the cause of this effect was the IV

what might a pilot involve for an observational study?

A pilot study provides a way of checking coding systems (a method of recording observations) before the real investigation is undertaken.

what might a pilot involve for a self-report (questionnaire/interview)?

* includes trying out questions in advance to remove or reword those that are ambiguous or confusing.

Explain why a single-blind procedure may be useful in reducing the effects of demand characteristics

If participants are made aware of the aims of the experiment at the outset, they may change their behaviour (particularly if they know which condition they are in). They may try too hard to make the experiment run smoothly (the 'please U effect') or attempt to sabotage the findings (the 'screw U effect').

If a single-blind procedure was used, explain what would need to happen at the end of the study?

If this procedure was used, participants would need to be given comprehensive details of the aims of the research during the debriefing. It would also be necessary to ask for permission to still use their data in light of the fact they had been deceived (albeit mildly).

Explain how you might set up a double-blind procedure

The drinks during the first phase of the experiment could be administered by a third party who does not know which drink is which and is unaware of the aim of the experiment.

Explain how a double-blind procedure would be effective in reducing investigator effects?

Without the knowledge of what the experiment is about, there is no way they could (consciously or unconsciously) communicate this to the participants.

Explain the purpose of the control group

The control group provides a comparison which allows the researcher to see whether the change in behaviour – if there is a change – is significant.