EXPERIMENTAL RESEARCH
– A method or procedure involving the control or manipulation of conditions for the purpose of studying the relative effects of various treatments applied to members of a sample, or of the same treatment applied to members of different samples.
– A highly controlled procedure in which manipulated treatments or actions from a factor or condition, called experimental or independent variable, are applied upon another factor or condition, called the dependent variable, to determine the effect of the former upon the latter, all other factors or variables being kept constant or equal so that any change in the dependent variable is attributable only to the experimental or independent variable.
– An attempt by the researcher to maintain control over all factors that may affect the result of an experiment. In doing this, the researcher attempts to determine or predict what may occur.
Purpose:
– To discover the influence of one or more factors upon a condition, group, or situation, purpose of which is to discover “what will be.” It describes and analyzes variables in carefully controlled conditions as a basic for inferring or concluding. An experimental research, therefore, consist of manipulating an experimental variable under highly controlled conditions to determine how and why a particular event occurs.
Terms:
Variables
– is anything that may change or may be changed from one condition to another, either qualitatively or quantitatively.
Independent Variable
– Anything, condition, or process which is controlled and manipulated by the experimenter and applied on another thing, condition, or process (dependent variable) intended to have or produce a change in or reaction from the latter.
Dependent Variable
– Anything, a condition, or process exposed to or upon which treatments or actions from the independent variable are applied. The response of or change in the dependent variable is measured and some statistical methods are applied to determine the effects of the independent or experimental variable.
Characteristics of Experiments
- Experimentation lends itself to easier manipulation because of quantitative entities.
- Observations are done under controlled conditions.
- Gathering of valid facts is rigorous,
- Experimentation can be conducted in the laboratory, in the classroom, or in the field.
- Laboratory experiments are intensive and exacting.
- Most often experiments are limited to a small number of cases.
- There is more thorough analysis of variable factors.
TYPES OF EXPERIMENTAL DESIGNS
- Single Factor Experimental Designs
1. Single group with only a post test
– This involves a thing, person, or group subjected or exposed to a certain experimental factor for a certain period of time. After the experimental period, the subject is given a post-test.
– The achievement of this experimental group is then compared with the achievement of another group with similar characteristics and studying the same subject matter under customary instructional methods but unexposed to the experimental factor.
– Any excess of the achievement of the experimental group over the achievement of the normal group is considered due to the experimental factor.
*The defect of this design is the absence of control over the variables involved. This is why, when interpretation is made of the result, variable that may have undue influence in the experiment should be given due consideration.
2. Single group with a pre-test and a post-test
– The group is exposed to a certain experimental factor. However, before the start of the experiment, the group is given a pre-test.
– After the experimental period, the group is given the same pre-test but in a different form to avoid the effect of practice. This is the post-test.
-The excess of the results of the post-test over the results of the pre-test is considered caused by the experimental factor.
3. Matched group
– In this design, two groups are matched in age, sex, grade level, mental ability, etc.
– One group or the experimental group is exposed to the experimental or independent variable while the other group or the control group is not exposed to the experimental variable. After the experimental period, the two groups are given the same test.
*It must be noted that all other variables except the independent variable are kept constant or equal during the experimental period.
– Any excess of the achievement of the experimental group over the achievement of the control group is attributed to the experimental factor.
4. Randomized multigroup with a post-test
– In this design, there are two or more experimental variables to be tested. So groups are formed equal to the number of experimental variables. The members of each group are assigned randomly to their respective groups.
– Each experimental factor is applied on the group to which it is assigned. All other variables, are kept equal in all the groups. After the
experimental period, the same test is given to all of them.
– The experimental factor assigned to the group with the highest achievement is considered the most effective; the experimental factor assigned to the group with the second highest achievement is the next most effective, and so on.
5. Randomized multigroup with a pre-test and a post test
– This is the same as the design in No. 4, the only difference is that, there is a pre-test.
B. Two Factor Experiment
Factorial Design
– This is a two factor experiment where two experimental factors are involved.
*Example:
We want to know the performance of a group of males and females in a learning situation under the effects of varying amounts of the same drug.
There are two factors here—gender (male or female) and dosage (amount of the drug).
In our analysis, we are concerned with difference in the learning related to (1) gender, (2) the amount of drug taken, and (3) the interaction effect of gender and drug.
Here, we have to make a two-way classification: classification of data according to gender, and classification of the same data according the drug dosage.
The achievement scores of the two groups after they have taken a post-test are subjected to analysis of variance which will reveal whether there is a significant difference between the learning capacity of males and that of females when under the effects of varying amounts of drug, and whether there is significant difference between scores of the whole group under the effects of the varying amounts of drug, and also the interaction between gender and drug, that Is, if the two factors helped each other.
ADVANTAGES
-Best establishes cause and effect relationships
-results can provide a starting point for further study
-existing studies can be further explored
-researcher has control over the process/variables
-determining interaction between variables is more possible
-can be repeated/several trials can be made
DISADVANTAGES
-can have inconsistencies
-since scientific method is a matter of human construction, it is subject to human error
-researcher’s Personal bias may intrude upon the experiment
-results may not be representative of a whole population
– Artificial results may result.
* It can be argued that variables are manipulated so the experiment measures what researchers want to examine.
BIBLIOGRAPHY:
Deflen, M. (1998). An Introduction to Research Design.
Retrieved September 21, 2009, from Mathieu Deflem’s Publications Website: http://www.cas.sc.edu/socy/faculty/deflem/zresdes.htm
Experimental. (1999. Retrieved, October 3, 2009 from
Research design in occupational education website: http://www.okstate.edu/ag/agedcm4h/academic/aged5980a/5980/newpage2.htm
Research overview. (n.d.). Retrieved, October 3, 2009 from
What is Research?* website: http://www.umdnj.edu/idsweb/idst6000/research_overview.htm#types_experimental
Calderon,J.F. (Eds.). (1993). Methods of research and
thesis writing. Mandaluyong: National Book Store.
Advantages and Disadvantages of Experimental Research:
Discussion.(2009). Retrieved September 21, 2009, from Writing Guides:Conducting Experiments Website: http://writing.colostate.edu/guides/research/experiment/pop5c.cfm
