For PhD one has to propose a hypothesis on the basis of literature and other information (pre existing). To prove this we define some objectives and apply the possible methods. PhD ends with either in agreement or disagreement to the hypothesis, well supported by the results we obtain. So, PhD is not always about agreements to the existing facts and theories, many time we end up by proposing new (disagreeing to the existing). But, you are asking about significant results, which is little confusing to me. Getting positive or negative results have their own connotations, so both are equally important. But, there should not be any technical flaw in our methodology, which could be responsible for the negativity or positivity of our results. The experiment designing and methodology are most important part for obtaining good results (negative or positive). If some body not able to find any results, which I believe is not possible, I will not recommend him for PhD award. If one conduct an experiment there are following options: it will support our hypothesis; or it will not; and several other options may be due to procedural errors (which is not the result).

Perhaps it can not be generalized about that.

For PhD one has to propose a hypothesis on the basis of literature and other information (pre existing). To prove this we define some objectives and apply the possible methods. PhD ends with either in agreement or disagreement to the hypothesis, well supported by the results we obtain. So, PhD is not always about agreements to the existing facts and theories, many time we end up by proposing new (disagreeing to the existing). But, you are asking about significant results, which is little confusing to me. Getting positive or negative results have their own connotations, so both are equally important. But, there should not be any technical flaw in our methodology, which could be responsible for the negativity or positivity of our results. The experiment designing and methodology are most important part for obtaining good results (negative or positive). If some body not able to find any results, which I believe is not possible, I will not recommend him for PhD award. If one conduct an experiment there are following options: it will support our hypothesis; or it will not; and several other options may be due to procedural errors (which is not the result).

The purpose of a PhD project is to learn how to do proper scientific research. When you defend your thesis you have to show that you were able to do such research. Finding only significant results is neither a necessary nor a sufficient condition for a successful defense. On the contrary. Significance often gets too much attention in social science research. Relevance of specific determinants, whether significant or not, is more important.

In PhD degree we learn how to address a problem and solve using various techniques, theories and hypothesis. A significant results are not necessary for a successful defense but sometime failure of experiment or non-significant results may give some new idea or lead for future experiments. But results should some relevance or support some previous hypothesis otherwise no use of PhD degree.

This is a very valid question. My personal opinion is that the quality of work has to be judged prior to the grant of the degree. Thesis is something that requires a lot of study to be incorporated along with judgemental definition of one's own problem. The problem that has been pinpointed by the researcher in a particular area has to be probed first. A particular solution to the problem may not be identified within the stipulated period of the research work. However that is not indicative of a poor work. Instead whatever has been done should be acknowledged as value addition in that particular area, encouraging further research on it. There are plenty of areas in Social Science where the researcher may not find any conclusive answer to the research question but the problem identified may itself lead to some major discovery.

Despite our best efforts to design the best study, a lack of significant findings can occur. Frequent reasons include lack of power, attrition, missing data, or an unexpected variable or sample issue. In human subjects research, we have less control over these problems, since subjects are volunteers. I would support the award of a doctoral degree to a student whose results did not reach statistical significance, if she demonstrated a sound rationale for the study, had conducted a power analysis based on the most recent data for effect size for the experimental intervention, had recruited a sample large enough to allow for a reasonable attrition rate, and who conducted the study in a sound matter, protected the rights of human subjects, and had conducted the appropriate statistical analyses. I would expect that the discussion section would include a thorough discussion about the lack of significant findings, including how to improve the research in the future, and the clinical implications of lack of significant findings. I agree with other authors in this topic area that research often leads to more questions, and these questions could lead us to important new knowledge.

The Ph.D. research is a training in developing and mastering research skills and to apply them to the real world problems. During this training programme one tries to formulate a research proposal to address the existing gap or inconsistency in the existing literature. As Rahi has rightly pointed out that a research proposal has a research objective and one or several testable hypotheses. Then one tries to collect evidences and these evidences may either support or fail to support your initial hypothesis. But in both condition you have a result or finding and either of the findings ( a significant or non-significant) need to be explained on the basis of availble literature and existing theories and models/hypotheses.

In my view obtaining a statistically significant result of a test is neither a requirement nor a necessity for any research including Ph. D. research. Sometimes, obtaining a non-significant result of a statistical test is requirement and sometimes it is not. it all depends on the objectives/hypotheses of one's research. For instance, if one is testing whether the sample data follows a normal probability distribution then a non-significant Chi Square test may be the desired outcome if normality is required and significant result may be the need if non-normality has been hypothesized.

Similarly, if one is interested in demonstrating that certain process, characteristics, trait, or phenomenon is stable over time and is state independent then he/she may be interested in obtaining a non-significant difference between the two measures of the given phenomenon obtained at two different points of time.

Further, even if one gets a result opposite (say a non-significant statistical test result) to the one hypothesized (a significant test result), it is not a problem until and unless this is because of some serious methodological problem/artefact. The only thing is that it requires more creative work to interpret the findings which is contrary to one's expectations as well as majority of the earlier findings in the area.

I have published some research where our hypothesis suggested a significant test results but we obtained the opposite. I am pasting link to one such publication here. We started this research with the idea that there would be difference in the exposed eye area of the left and right eye during facial expression of emotions. However, we could not find any statistical support for this hypothesis but we do noted that eye area differed for different emotions.

https://www.researchgate.net/publication/21664962_Exposed_eye_area_%28EEA%29_in_the_expression_of_various_emotions?ev=prf_pub

Article Exposed Eye Area (EEA) in the Expression of Various Emotions

Can a PhD. candidate get his degree without finding any significant (p.05) can be a significant finding.

After rigorous literature review a hypothesis is proposed in which objectives are formed as per the literature gap. These objectives are solved by certain possible valid methods. At the end the results are validated with the literature available which must not be violate the basic principles in general. So, during PhD a candidate is trained to carry out research and to develop critical thinking under the given circumstances and problems. May be in few rare cases there will not be any creative outcome, so it really instigates supervisor to think about the candidate future.

Nice query@ Chih-Long Yen