1Department of Preventive Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
2Ulsan Metropolitan City Public Health Policy’s Institute, Ulsan, Korea
3Department of Nursing, Chung-Ang University, Seoul, Korea
4College of Nursing, Sungshin Women’s University, Seoul, Korea
5Department of Preventive Medicine, University of Ulsan College of Medicine, Seoul, Korea
Copyright © 2023 The Korean Society for Preventive Medicine
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Characteristics | Quantitative research | Qualitative research |
---|---|---|
Research purpose | Test the validity of the hypotheses established by the researcher to identify the causal relationships and laws of the phenomenon and predict the phenomenon | Discover and explore new hypotheses or theories based on a deep understanding of the meaning of the phenomenon |
Perspective on variables | View factors other than the variables of interest as factors to be controlled and minimize the influence of confounding factors | View factors as natural and accept assessments in a natural environment |
Research view | Objective, outsider view | Intersubjective, insider view |
Data used | Quantifiable, measurable data | Narrative data that can be expressed by words, images and so on |
Data collection method | Primarily questionnaire surveys or tests | Primarily participant observation, in-depth interviews, and focus group discussions |
Nature of data and depth of analysis | Focus on superficial aspects of the phenomenon by using reliable data obtained through repeated measurements | The aim is to identify the specific contents, dynamics, and processes inherent within the phenomenon and situation using deep and rich data |
Strengths and weaknesses | High reliability and generalizability | High validity |
Difficulties with in-depth analysis of dynamic phenomena that cannot be expressed by numbers alone; difficulties in interpreting the results analyzed by numbers | Weak generalizability; interjection of subjectivity of the researcher is inevitable |
Sampling method | Explanation |
---|---|
Typical sampling | Selecting the most typical environment and people for the research topic |
Unique sampling (extreme case sampling) | Selecting unique and uncommon situations or subjects who satisfy the research purpose |
Maximum variation sampling | Selecting subjects showing maximum variation with a target population |
Convenience sampling | Selecting subjects who can be sampled most conveniently considering practical limitations, such as funding, time, and location |
Snowballing sampling | Selecting key research participants who satisfy the criteria established by the researcher and using their recommendations to recruit additional research participants |
Classification | Specific method | Characteristics |
---|---|---|
Level of structuralization | Structured interview | Data are collected by asking closed questions in the order provided by highly specific interview guidelines |
Useful for asking questions without omitting any details that should be checked with each research participant | ||
Leaves little room for different interpretations of the participant’s responses or expressing original thoughts | ||
Semi-structured interview | Between a structured and unstructured interview; interview guidelines are developed in advance, but the questions are not strictly set and may vary | |
The most widely used data collection method in qualitative research, as it allows interviews to be conducted flexibly depending on the characteristics and responses of the participants | ||
Researcher bias may influence the interview process | ||
Unstructured interview | The interview is conducted like a regular conversation, with extremely minimal prior information about the research topic and adherence to interview guidelines to exclude the intention for acquiring information needed for the research | |
Can obtain rich and realistic meaning and experiences of the research participants | ||
The quality of information acquired and length (duration) of interview may vary depending on the competency of the interviewer, such as conversational skills and reasoning ability | ||
Sample size | One-on-one in-depth interview | Excluding cases in which a guardian must accompany the research participant, such elderly or frail patients and children, a single participant discusses the research topic with one to two researchers during each interview session |
This data collection method is recommended for research topics that are difficult to discuss with others and suitable for obtaining in-depth opinions and experiences from individual participants | ||
The range of information that can be acquired may vary depending on the conversational skills and interview experience of the interviewer and requires a relatively large amount of effort to collect sufficient data | ||
Focus group discussion | At least 2 (generally 4–8) participants discuss the research topic during each interview session led by the researcher | |
This method is effective when conducting interviews with participants who may be more willing to open up about themselves in a group setting than when alone, such as children and adolescents | ||
Richer experiences and opinions can be derived by promoting interaction within the group | ||
While it can be an effective data collection method, there may be some limitations in the depth of the interview; some participants may feel left out or not share their opinion if 1 or 2 participants dominate the discussion | ||
Interview method | Face-to-face | The interviewer personally meets with the research participant to conduct the interview |
It is relatively easy to build rapport between the research participant and interviewer; can respond properly to the interview process by identifying non-verbal messages | ||
Cannot conduct interviews with research participants who are difficult to meet face-to-face | ||
Non-face-to-face | Interview between the interviewer and research participant is conducted through telephone, videoconferencing, or email | |
Suitable data collection method for topics that deal with political or ethical matters or intimate personal issues; in particular, email interviews allow sufficient time for the research participant to think before responding | ||
It is not easy to generate interactions between the research participant and interviewer; in particular, it is difficult to obtain honest experiences through email interviews, and there is the possibility of misinterpreting the responses |