Field Experiments take place in a real-life settings such as a classroom, the work place or even the high street. Field experiments are much more common in Sociology than laboratory experiments. In fact sociologists hardly ever use lab experiments because the artificial environment of the laboratory is so far removed from real-life that most Sociologists believe that the results gained from such experiments tell us very little about how respondents would actually act in real life.
It is actually quite easy to set up a field experiment. If you wanted to measure the effectiveness of different teaching methods on educational performance in a school for example, all you would need to do is to get teachers to administer a short test to measure current performance levels, and then get them to change one aspect of their teaching for one class, or for as sample of some pupils, but not for the others, for a period of time (say one term) and then measure and compare the results of all pupils at the end.
The advantages of Field Experiments over Lab Experiments
Better external validity – The big advantage which field experiments obviously have better external validity than lab experiments, because they take place in normally occurring social settings.
Larger Scale Settings – Practically it is possible to do field experiments in large institutions – in schools or workplaces in which thousands of people interact for example, which isn’t possible in laboratory experiments.
The disadvantages of Field Experiments compared to Lab Experiments
It is not possible to control variables as closely as with laboratory experiments – With the Rosenthal and Jacobson experiment, for example we simply don’t know what else might have influenced the ‘spurting group’ besides ‘higher teacher expectations’.
The Hawthorne Effect (or Experimental Effect) may reduce the validity of results. The Hawthorne effect is where respondents may act differently just because they know they are part of an experiment. The Hawthorne Effect was a phrase coined by Elton Mayo (1927) who did research into workers’ productivity at the Western Electric Company’s Hawthorne plant. With the workers agreement (they knew that an experiment was taking place, and the purpose of the experiment), Mayo set about varying things such as lighting levels, the speed of conveyor belts and toilet breaks. However, whatever he did, the worker’s productivity always increased from the norm, even when conditions were worsened. He concluded that the respondents were simply trying to please the researcher. NB – The Hawthorne effect can also apply to laboratory experiments.
Practical Problems – Access is likely to be more of a problem with lab experiments. Schools and workplaces might be reluctant to allow researchers in.
Ethical Problems – Just as with lab experiments – it is often possible to not inform people that an experiment is taking place in order for them to act naturally, so the issues of deception and lack of informed consent apply here too, as does the issue of harm.
Rosenthal and Jacobson’s 1968 Field Experiment on Teacher Expectations (Pygmalion in the Classroom)
This classic field experiment illustrates some of the strengths and limitation of this method.
The aim of this research was to measure the effect of high teacher expectation on the educational performance of pupils.
Rosenthal and Jacobson carried out their research in a California primary school they called ‘Oak School’. Pupils were given an IQ test and on the basis of this R and J informed teachers that 20% of the pupils were likely ‘spurt’ academically in the next year. In reality, however, the 20% were randomly selected.
All of the pupils were re-tested 8 months later and he spurters had gained 12 IQ points compared to an average of 8.
Rosenthal and Jacobsen concluded that higher teacher expectations were responsible for this difference in achievement.
Limitations of the Experiment
Firstly, deception/ Lack of Informed Consent is an issue – In order for the experiment to work, R and J had to deceive the teachers about the real nature of the experiment, and the pupils had no idea what was going on.
Secondly, there are ethical problems – while the spurters seem to have benefited from this study, the other 80% of pupils did not, in fact it is possible that they were harmed because of the teachers giving disproportionate amounts of attention to the spurting group. Given that child rights and child welfare are more central to education today it is unlikely that such an experiment would be allowed to take place.
Thirdly, reliability is a problem while the research design was relatively simple and thus easy to repeat (in fact within five years of the original study this was repeated 242 times) the exact conditions are not possible to repeat – given differences between schools and the type and mixture of pupils who attend different schools.
Finally, it’s not possible to rule out the role of extraneous variables. Rosenthal and Jacobson claim that higher teacher expectation led to the higher achievement of the ‘spurters’ but they did not conduct any observations of this taking place. It may have been other factors.
Are Chinese Teaching Methods the Best? – A Field Experiment in ‘tough teaching methods’ in the UK conducted in 2015.
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