Critique Of An Experimental Study

By Jill Akers


Wisher, R. & Curnow, C. (1999). Perceptions and Effects of Image Transmissions during Internet-Based Training. The American Journal of Distance Education,13 (3), 37-51.


The relationship investigated in the study pertains to whether or not image transmission, specifically the transmission of the instructor's image, effects learning facts.

Type of Design:

The independent variable is the video image of the instructor manipulated in an on or off situation. The participants' perceptions of their ability to learn and the effectiveness of the instructor are compared in a multi-source evaluation. Also, perceptions of the effects of transmission lags were compared to learning. Finally, face-to-face teacher instruction is compared to Audiographics instruction using test scores.

Factors Jeopardizing Internal Validity:

Experimental mortality could be a changing factor in this experiment. Given that the participants are in the armed forces they might possibly die in weekly training accidents or be sent to war between lessons.

Factors Jeopardizing External Validity:

Reactive effects of experimental arrangements might change the generalizations of an experiment. Since the instruction is spread out between two weekends, participants experiences at work during the week could increase perceived knowledge and decrease the learned knowledge measured by the test at the end of the experiment.

Adequacy of Statistical Procedures Used:

At this time I have not identified any inappropriate use of statistics to compare differences and I have no suggestions for improvements.

Briefly Summarize Logic (Inductive and/or Deductive):

The authors use both forms of logic, because the use conclusions formed in other research along with empirical results to form generalized and specific conclusions.

Design Improvement:

No modifications are needed other than using consecutive days experiment.

Extension of the Study:

At this time, the extensions that I can think of were done in previous tests and noted in the article.