Hi

Sometimes the operational definition of an instrument can be outdated.   If an  author's definition was cited in a sound refereed journal, a source of an authorized technical data base, one shouldn't  fear not to use the author definition with citation of the source.  

Dear Arif,

This is indeed tricky.  In my experience it is not unusual - even for people who get  published in presumably reputable journals - to fail to see a mismatch between what they claim to be measuring and what they actually measure.  For example, I recently reviewed four pieces of published research in which the researchers claimed to be measuring intra- and inter-rater reliability concerning blood pressures (BPs) but it was pretty obvious from looking carefully at what they had done that they were not actually measuring either kind of rater reliability but rather were tapping fluctuations in their participants' blood pressures: They were measuring participant consistency, not rater consistency. This was particularly evident because two of the sets of researchers were using fully automated equipment to assess BPs, so there was essentially no or minimal opportunity for variations caused by the raters. By carefully comparing all of their results, and some other research, I concluded that all of the four sets of researchers were barking up the wrong tree. In a way, that didn't surprise me because of a range of other problems in each of the publications. (My article is currently under review with a journal that has a better reputation than any of the journals in which the articles I am criticising appear. Who knows whether my article will be accepted or not, so I need to exercise a degree of humility / caution.)

So, from my recent experience, I would argue that if published researchers can fail to match up what they think they are measuring with what they are actually measuring,  it's not surprising that an undergraduate student would do the same.

This is somewhat related to the well-known phenomenon of the drunkard's search, or streetlight effect, in which people conduct research where it is easiest, not where it is most appropriate.  Your student, in this case, could have chosen the instrument because it was the easiest one to use, overlooking the fact that it was not fit for purpose. 

Whatever the reason for your student doing this, you need to decide what to do.  I daresay you are assessing the student's work.  Presumably you have a marking scheme and if other aspects of the student's thesis are highly satisfactory it might not attract a bad mark despite the major conceptual flaw.

One final thing:  Sometimes good instruments' overt characteristics (i.e., what their items look like) might not match up with what they are actually measuring.  For example, an item "I like to collect butterflies" might not be related as much to a person's hobbies but to whether or not the person would enjoy the occupation of librarian rather than Arctic explorer or brain surgeon - so it is important to know what an instrument actually purports to measure as opposed to what it overtly appears to measure.  Maybe, after all, your student's instrument does measure what they student claims to be investigating.  That is worth checking out.

I hope this is helpful.

Robt.

Thank you Khalid for your reply and Robert for your comprehensive explanation. It is true that such articles can be found in some journals. Given the inflationary marking trends in our universities, I did not tease the student that much but just to let him know that this is an issue to look for when designing research studies in future.

Dear Arif

The purpose of  technical/scientific communications via articles of peer refereed journals is to covey to technical/public communities the latest state of the art & technology on issues relating to modification/ updating/ innovation of solution approaches of different problems.   So, papers of refereed journals should be an excellent source of data base that one should refer to and then cite.  

So, sometimes standard instructions of  an instrument are not enough for a student to follow during a thesis work.   Therefore, researching for updated instructions would be good enough to achieve a reasonable thesis work.            

Dear Arif

A bachelor level thesis, As long As the explain there is difference between the constructed definition and measuring scale, the the Operational definition) the difference among marketers. Is enough.