• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Internal and External validity.

Extracts from this document...

Introduction

Internal Validity is the approximate truth about inferences regarding cause-effect or causal relationships. Thus, internal validity is only relevant in studies that try to establish a causal relationship. It's not relevant in most observational or descriptive studies, for instance. But for studies that assess the effects of social programs or interventions, internal validity is perhaps the primary consideration. In those contexts, you would like to be able to conclude that your program or treatment made a difference -- it improved test scores or reduced symptom logy. But there may be lots of reasons, other than your program, why test scores may improve or symptoms may reduce. External validity concerns making generalizations about your results. That is, how well do the conclusions of your study apply to other people in other places at other times? ...read more.

Middle

To the degree that we are successful in eliminating confounding variables within the study itself is referred to as internal validity. External and internal validity are not all-or-none, black-and-white, present-or-absent dimensions of an experimental design. Validity varies along a continuum from low to high. One major source of confounding arises from non-random patterns in the membership of participants in the study, or within groups in the study. This can affect internal and external validity in a variety of ways, none of which are necessarily predictable. It is often only after doing a great deal of work that we discover that some glitch in our procedures or some oversight has rendered our results uninterruptible. Pre-experimental: In general, a research design is like a blueprint for the research. ...read more.

Conclusion

Because of this, we can have considerable confidence that any differences between treatment group and control group are due to the treatment. Another true experimental design is the Solomon Four-Group Design which is more sophisticated in that four different comparison groups are used. The major advantage of the Solomon design is that it can tell us whether changes in the dependent variable are due to some interaction effect between the pretest and the treatment. For example, let's say we wanted to assess the effect on attitude about police officers (the dependent variable) after receiving positive information about a group of police officers' community service work (the independent variable). During the pretest, the groups are asked questions regarding their attitudes toward police officers. Next, they are exposed to the experimental treatment: newspaper articles reporting on civic deeds and rescue efforts of members of the police department. MGT333 Assignment 4 TO Miss Sue By Peter 19th. Feb. 2004 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Design and Technology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Design and Technology essays

  1. Management concerns.

    Chairman The concern of the chairman when choosing between the two machines is that will the new technology conch help them be more competitive. Section 2 Market environment The UK chocolate confectionery market is lead by three companies, Cadbury, the market leader, closely followed by Rowntree-Nestle and Mars.

  2. Single portfolio item: The decision to refurbish

    Defects exist of serious nature or defects requiring urgent repair Glover, P (2009), P156 What is important is that the government is seen to work towards improving the large stock of dwellings with in the United Kingdom (UK) that need to be graded into energy ratings and of which then

  1. Free essay

    Buiklding service

    or tight bends along my water pipes, against its direction of flow. In my water system back pressure does occur at various outlets and at the boiler when there is reversed water pressure. Back siphonage occurs when the water supply pressure drops in our cold water system; it is a

  2. Free essay

    Systems Case Study

    so I want to know where the majority of the money goes and what area is concentrated on and why. The system at Canary Wharf has many measures to ensure a safe environment around the company with complex and simple measures.

  1. Nano technology - Screen technology is a fast changing technology area.

    Improving sustainability and safety of industrial systems - Integrating nanotechnologies and new material into production systems will help introduce new designs and new ways of making things smaller, cheaper, better to run, fighting pollution and developing clean and less source intensive technologies.

  2. The proposed design project is to design, produce and evaluate an innovative recycled clock, ...

    23/05/02 25/05/02 Selection of appropriate folio paper 24/05/02 Project proposal 24/05/02 23/05/02 Go to Newtown to purchase materials 24/05/02 Go to Marrickville 24/05/02 Action/Time plan 25/05/02 23/05/02 Finance plan 12/06/02 Concept sketches 28/05/02 30/06/02 Technical drawings 28/05/02 Experiments 29/05/02 Ideas 02/06/02 25/05/02 Construct Clock 13/06/02 22/06/02 Ongoing evaluation - 23/06/02

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work