EXPERIMENTAL RESEARCH:

One of  the other method used  in  research  is Experimental Research. 

Meaning and Characteristics 

Experimental research is concerned with  cause and  effect relationship. To qualify as an experiment, a research design need only posses the following three properties: 

1)  Manipulation -  The researcher manipulates some of the  subjects. 

2)  Control -  Researcher introduces one or more controls over  the experimental situation, including the use of a control group. 

3)  Randomization -  Researcher assigns subject to a control or experimental group on  random basis.  

Let us suppose you want  to  test  the effects of  information gained  through an organized pre-natal health teaching programmes, e.g.  "group  approach. You also want  to  know whether your  teaching would make the difference or something else which  is not  in your  control. That means you want to study  the possible cause and  effect relationship by  exposing one group (experimental group) to  a "treatment"  and then compare the results with  the findings of another group (control group) which  is not exposed to the "treatment".  The "treatment"  in  this example  is an organized pre-natal  health  teaching programme but  it can also be  drugs, conditions, procedure, nutrients, etc. One of  the simplest true experimental designs is called the pretest-post-test  control group design as shown in Fig.  

pretests  (Knowledge test) both  groups (Represented by  symbol  0,) exposes the experimental group to  the  teaching (symbol x) and  then post tests (same as knowledge  test in pre-test) both  groups (represented by  symbol 0,).  All conditions except "teaching"  should remain the  same for both groups. The investigator can  find  the  difference of  the measures for both  groups  and compare  the groups on  the  selected variable. Refer to Unit  1 where you  have  learnt  about variables. Can you  identify the independent variable and  the dependent variable? The variable  i.e. considered as the  "cause"  is  "teaching "whereas the variable as "effect"  is knowledge score" as measured by  pre- or post-test  is  the dependent variable. The control group  is necessary to make  sure that  it  is  the "treatment"  or  the "teaching"  that has  caused the knowledge  increase and not  something else, because  if  there is something else (such as radio or TV  talk)  then  control group will  also be exposed  to  this  and you will not  find  the  difference in knowledge between  experimental and control groups. The very  fact that  there  is  a difference between  these two groups, the  investigator logically says that  the "treatment"  given has made  the'difference.