Dear Gopinath,

There is no best research approach. Researches are basically a configurations of  formulated goals, research paradigm of particular researcher, methods, techniques,  habitus and personal predispositions. If someone considers this all mentioned issues, he/she  will find  him/herrself somwhere on horizon of scientific researches. For me leading the research is far more than only mechanical choosing  the methodology.

For me, the answer to this question is similar to the explanation in the poem I read more than four decades ago, "The Mountain and the Squirrel". The discussion between the mountain and the squirrel ended up to the conclusion that "talents differ, all is well and wisely put".

Dear Gopinath,  Good Morning

Qualitative research is by definition exploratory, and it is used when we don’t know what to expect, to define the problem or develop an approach to the problem. It’s also used to go deeper into issues of interest and explore nuances related to the problem at hand. Common data collection methods used in qualitative research are focus groups, triads, dyads, in-depth interviews, uninterrupted observation, bulletin boards, and ethnographic participation/observation.  In this method, man power, materials and expenses are more.

Quantitative research is conclusive in its purpose as it tries to quantify the problem and understand how prevalent it is by looking for projectable results to a larger population. Here we collect data through surveys (online, phone, paper), audits, points of purchase (purchase transactions), and click-streams.   In this method, man power, materials and expenses are very minimized (less than the previous method).

So, you have to do more focus on the groups is a substitute for quantitative research or that a long survey will give you all the in-depth information you can get though qualitative research methods.

For more information see the attachment.

Dear Gopinath,

There is no best research approach. Researches are basically a configurations of  formulated goals, research paradigm of particular researcher, methods, techniques,  habitus and personal predispositions. If someone considers this all mentioned issues, he/she  will find  him/herrself somwhere on horizon of scientific researches. For me leading the research is far more than only mechanical choosing  the methodology.

There is as such no one method which can be termed as best to a research project. Qualitative or Quantitative depends on the degree of search which a researcher envisages, example.

Macro detailing - Qualitative Methods

Micro detailing - Quantitative Methods

Workable / implementation detail - Quasi Quali-Qunti method.

Only measurable data are being gathered and analyzed in quantitative research.

Qualitative research focuses on gathering of mainly verbal data rather than measurements. Gathered information is then analyzed in an interpretative manner, subjective, impressionistic or even diagnostic. It depends upon our research design.

https://explorable.com/quantitative-and-qualitative-research

"According to the research methodology literature quantitative research paradigm was accepted as the first phase while the qualitative research paradigm was emerged as an alternative to it and was conceptualized as the opposite of quantitative paradigm. As many researchers started advocating in mixing both quantitative and qualitative methods, resulted to established mixed research method paradigm."

Conference Paper MIXED RESEARCH METHOD AS THE THIRD RESEARCH PARADIGM A LITER...

You may find some good answers in the following threads!

https://www.researchgate.net/post/Is_quantitative_research_or_qualitative_research_more_popular_in_your_country?_sg=o4FP%2BC3a6Na6up3IR4rQU6rwyl91bcqpebyiyzDP2jtnhrPNyPXKJfx0v8kknNjU_VGKVASD4MkqqMjbiDSAwYSnA1Vg9FMPQJn2GiGZzuJUjxWzF25NWx%2BG4y6wgyov%2F_eN0TFjmRxkBj6leMMJztZ2oz8FHE1%2Fsj3%2FF5eaJVXlbwjSi4rePwsHHaVGcUtd4F&_tpcectx=search

https://www.researchgate.net/post/Is_qualitative_research_less_scientific_than_quantitative?_sg=SG5UgOzCbMlX8KoseR5qXBbOVe0Vyq467Qy%2FVg8q%2Feg68qy9qNzhFf%2B%2B8Y%2BkPxO6_1vx7enWCFcsgVtcRHlN3LyBA35H8UWTaM5jG5exLOKWZhSNxW108Sz2e%2BCtJbHj0_snnsgzF9Lq%2BQa0PGE1Ec5fnH0nIrIi6Z8ys04%2B0mqPUTVVaDcXhRiAGvAej%2FkZOq&_tpcectx=search

https://www.researchgate.net/post/Is_qualitative_research_inferior_then_quantitative_research?_sg=xl5lWplYlv6e%2BOpoXg9UHNmfVefuNidhyPxroVuz55G%2BPWXyfp2g29fLoaabnRgX_nBJFgDMdrjPMapP7xoAyUvQBwasQb3GrW0gj6bojRXLkUbLeEBVVPaj9SVPuKWs4_s68HYOen%2BYwOofUOA%2Fsimq7aLwwlJnZHIvoWdF7f8NUThMT0xOcdxDnPN6IIeNtD&_tpcectx=search

@ Prof. Ljubomir Jacić, Thank you  for your sources to know about  more information of qualitative and quantitative research.  

In Case study both qualitative or quantitative approaches can be applied

Qualitative 

Depth analysis of a single or small number of units, single person,  group of people, organisation or institution, Some CS research may involve series of cases.

Complex analysis - over a period of time, extended case study, traces events of same people reflecting changes and adjustments. Offer a richness and depth of information by capturing as many variables as possible to identify how a complex set of circumstances come together to produce a particular manifestation.

Quantitative

Used to find out how much, how many, how often, to what extent its approaches to constructing social theories, assess and measure a way to get to the crux of understanding, predicting and control cause and effect relationships.

Dear Prof. Krishnan, Thanks for your practical oriented information about qualititative & quantitative research. It's very useful to the researcher.

Qualitative Research  / Quantitative Research Method - it all depends on need and goals/aims of a researcher --- both can be adapted in a team mode and good spirit with a nice balance and hard works

Both qualitative as well as quantitative research methods are good depending on how well the balance is maintained, nature and objective of the research work.

The debate on Quantitative/Qualitative divergence and sometimes the dominance of one over the other has a long story; however, the basis which requires the use of one rather the other relies on the essence of the research topic. Clearly, the matter of superiority is illogical. We do not pick a methodology for research; the research purposes determine what methodology would be best fitted for the study. In the simplest of ways, if we are out to scrutinize a phenomenon about which little is realized and you do not realize what to expect, we employ qualitative methods. On the other hand, if we are out to gauge variables utilizing an existing of the self-created questionnaire and then carry out statistical analysis to accept or reject our hypothesis, we may use quantitative methods. We may also want to utilize both in some cases.

Dear @Dr. GOPINATH, I do find the following research question important and related to yours. 

https://www.researchgate.net/post/Does_anyone_have_knowledge_on_convergent_parallel_and_embedded_mixed_methods_research

Dear @Ali, this is good reading for young researchers.

https://he.palgrave.com/studentstudyskills/page/choosing-appropriate-research-methodologies/