Advantages and Limitations:

Experimental  approach represents the most  powerful method for  testing hypothesis of  the  cause and  effect relationship between variable. Because of its special controlling properties on  experiment it offers greater control than any 

other  research approach that the independent variable  (e.g.  diet,  drug, dosage, teaching  approach) has an effect  on the dependent variable  (e.g. weight  loss, recovery  of health, learning,  etc.). The  great strength  of experiments then  lies  inthe  confidence with which casual relationship  can be  inferred. 

Limitations:

This  approach has several  limitations. Many interesting variables are not  amendable to experimental manipulation. A  large number of human characteristics  e.g. health history, age, gender, can not  be  randomly conferred on people. 

• Many variable  can be  technically manipulated but  ethical consideration prohibit  their manipulation  e.g.  experimentation  with humans would have an  ethical constraints. 
• In many situations experimentation  may  not  be feasible, because  it is impractical  for example in hospital,  etc. 

Another problem  in  experiment is Hawthorne  effect  or placebo effect.  It  is  the effect  on  the  dependent variables caused by subject's  awareness, that they  are special participants  under  study  e.g.  the  knowledge of being  included  in the study may  be sufficient  to cause people  to  change their behaviour.  For  examplewhen a staff nurse knows that  slhe has involvement in  research to  find  the quality  care being  offered,  itself will improve the quality of care.