Yes I think a thesis with negative results would be acceptable if it's all theorems and postulates were true. In fact, if you focus on science history, the most of researches with negative results put important impacts on science promotion or perhaps resulted in a science revolution.

Thanks a lot Dr. Abbasian for expressing your views. I truley agree with you that if the results (negative results) are confirmed, it is very important to present it before the scientific community beacuse the so called negative results, though not valued much by many of the researhers are in fact an integral part of scientific progress.

I agree with K. A.

The results of a thesis, regardless of whether they are positive or negative do not reflect the quality of the achieved scientific work. For example, if you depart with a theory in mind and prove that it does not work in your specific context as reflected by the results obtained, it is also a valuable contribution to knowledge.

I think it all depends on the amount of scientific ingenuity used and presented in the thesis or reports. If someone would award me a PhD for showing that the length of men's (and women's) noses do not correlate with their IQs, I'd be very disappointed regarding the value of the PhD.

I'm agree with Michael, Muhammad and Mohamed. As a student, my teachers told me that the thesis with negative results were unacceptable; however, now that I am a teacher and work with students who are doing their thesis, I am convinced that if their works have the necessary scientific rigor, the negative results are useful, particularly for other researchers in the field.

My teachers said that a negative result is a result and as good as a positive one. Important are your working methods, how you present your work, how you put your argumentation etc. These things show the qualitiy of the scientific work.

You can always couch your hypothesis the other way around: "The purpose of this thesis is to show that A does NOT affect B", and prove that you are right! (But, does the reasonable person expect A to affect B?)

Hi All, It should be because results of any research are ultimately results. There is always two dimensions of accepting or rejecting any null hypothesis. Thanks

It is very old question on RG.

Yes, Degree may be awarded if you are certain that the research problem does not hold true or received theory has gone wrong somewhere.

If it is an experimental research, repeat your experiment in control conditions at least three times to be doubly assured that results of experiments are what you think they are.

In the case of field data, one has to collect data using different sampling strategy, so there is no doubt that data are negating what previously has been believed.

Your contribution will be highly valued and accepted for the Degree, if your findings are not against the findings of your supervisor, members of evaluation committee or some higher one in the hierarchy or against the perception which the establishment wants to maintain. As far as supervisor and members of evaluation committee are considered, generally they have dignity to accept what is present contrary to their views. I cannot anything about others.

Yes. I don't believe you went into research with the perception that you would have a positive result as that would be ethically meaningless since the condition upon which the research was conducted was to test certain number of hypothesis (null & alternative). If the results are positive you could be confirming what others had previously confirmed or confirming a novel idea or findings. If it is negative on the other hand, you are either disproving what has being approved by other researchers or disapproving a tested hypothesis. In any case, the degree should be awarded because the essence is to see your methods, data collection and analysis and how those answer your research questions and that could either be positive or negative. If a supervisor refuses to accept your work, he or she misses his or her role.

PhD should never been awarded if there are no novel positive findings but definitely, negative ones are still considered helpful as it shortens the way for others

I think that a Ph. D degree should be awarded for a complete, comprehensive, research that concludes some results whether these results are negative or positive; but a Ph. D degree can not be  awarded for incomplete studies.

The purpose of research is to ferret out the truth. And the truth could either be positive or negative. The degree must be awarded either way (results).

I think a PhD degree can be awarded even though the thesis contained negative results provided there are strong justifications by the researcher why and how the negative findings are developed i.e. which are not in line with mainstream findings or theoretical frameworks s/he had underpinned on.  If the strong justifications are valid the negative findings might be knowledge contribution also.

Yes, must be awarded PhD,  for research, negative result, or negative thought is also of same importance. Newton, thought,' Why apple has not gone up?', and found the gravitation, and its laws.......