• 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. Free essay

    Buiklding service

    result of liquids at a lower level drawing water from a higher level. Back siphonage is a plumbing term applied to clean water pipes that connect directly into a reservoir without an air gap. In our cold water system, as our water is delivered to other outlets and areas of

  1. Free essay

    Systems Case Study

    The information, which I have processed and explained on the page before, will be gathered and collected using a number of sources, both primary and secondary. My main source of information will be through an interview with the head of the I.T.

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

    However the skill of decoupage was one I still had to achieve. I was lucky enough that Miss Brett had some scrap pieces of timber left over from previous work done by design and technology students. I researched a theme that was a retro style; I wanted something different to everybody else's so this was the project for me.

  1. Single portfolio item: The decision to refurbish

    item to in more than one ways to fit into the whole-life cycle of a building. Put in lay mans terms what works needs to be done (if any). The report itself was in 4 parts as identified in table 1 below.

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

    Expect SEDs to offer more brightness and contrast than plasma at a cheaper price with the same slim, sexy profile and screen size. HEED Pioneer's research in flat-panel display has taken it into the development of high-efficiency electro-emission devices (HEEDs).

  1. Investigating the effects of heat treatment on metals.

    In annealing, copper by far was the strongest metal where the average number of bends was 75. Aluminum and steel however, only bent 32 and 35 times, respectively. This shows that annealing heat treatment does little in increasing the strength of steel and aluminum.

  2. The Differences and Assimilation of Chinese and American Diet

    When the United States announced their diet food products to China, they were advertising that their food is more effective on the combination of nutrition than Chinese diet. The food industry is more developed, their cans, fast food are much better than what Chinese people usually eat.

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