Data Collection Methods and Instruments
Research instruments refers to the tools you are going to use to answer your objectives.
The researcher is supposed to explain the different methods that he/she intends to use during data collection. However, the research must put into consideration the research approach adopted (Qualitative, Quantitative or Mixed Methods), this will help the researcher in choosing the most appropriate research method to adopt.
Furthermore the researcher should as well put into consideration the type of data to be collected whether its primary data, Secondary data or a combination of both primary and secondary data. This will equally guide during the process of selecting the most appropriate data collection methods.
Note that:
The choice of data collection method (s) to be adopted by the researcher depends of the research approach used and the more the data collection methods adopted the more hectic the research but the better the findings.
Some of the data collection methods include; Questionnaire Survey, Interviews, Documentary Review, Focus Group Discussions, Observations and Experiments among others.
Data collection instruments
The primary methods employed for data collection consist of:
Data collection instruments refer to the tools that the researcher will use for collecting the relevant data related to the study objectives.
The researcher is therefore supposed to use this section to discuss the different data collection instruments s/he will adopt during the research, to state the data collection instrument, then briefly explain how it will be structured and the types of questions you expect to ask using the instrument.
For the case of questionnaires and interviews, the researcher must clearly state whether they will be structured or not & whether they will be self-administered or not. Therefore, the researcher is supposed to provide the basic information about the data collection instrument that will be adopted.
Questionnaire or Questionnaire Guide
While as the data collection method was a questionnaire survey, its corresponding data collection instrument is the questionnaire or a questionnaire guide.
The researcher is therefore supposed to briefly explain what a questionnaire is, explain how the questionnaire will be structured, explain the types of questions that you have in the instrument (whether open-ended, closed ended or both), explain whether you will use a Likert scale questionnaire or instrument, explain whether the questionnaire will be mailed, self-administered or web-based and as well explain whether it will be a structured, semi-structured or unstructured instrument.
This section is supposed to enable the reader understand how your questionnaire will be composed.
Interview Guide
In the case that the researcher adopted interviews or interviewing as the data collection method, then the data collection instrument would be the interview guide.
An interview guide is therefore a data collection instrument that supports the researcher through directing an interview process towards the objectives and issues regarding the study.
The researcher is therefore supposed to briefly explain what an interview guide is, explain how the interview guide will be structured, explain the types of questions that will be asked (whether open-ended, closed-ended or mixed), explain whether it will be a structured, unstructured or semi-structured interview, The researcher is also supposed to explain whether it will be a Directly personal interview, Telephone interview, Panel interview, Group interview or a Video conferencing interview.
This section is supposed to enable the reader to understand all the questions of; Who, Why, When, How and Where about your interview guide.
Observation Checklist
While as the data collection method was observation, its corresponding data collection instrument is the observation checklist.
An observation checklist is therefore a list of items that a researcher/ observer intends to observe (look at, hear, taste, smell or touch) during the data collection process.
The researcher is therefore supposed to briefly explain what an observation checklist is, how an observation checklist will be structured, explain the items in the observation checklist and further explain for how long he/she intends to observe. Say everything about your observation checklist.
This section is supposed to explain whether the observation will be; Participatory, Non-participatory or Covert-observation and how it will be executed.
Therefore, this section is supposed to enable the reader understand how your observation checklist will be composed.
Focus Group Discussion Guide
Researchers must note that if the data collection method was Focus Group Discussion, then the data collection instrument is a Focus Group Discussion Guide.
A Focus Group Discussion Guide is a data collection instrument that supports the researcher through streamlining particular processes or advising on how the Focus Group Discussion will be conducted in order to achieve its predetermined objectives.
The researcher is therefore supposed to briefly explain what a Focus Group Discussion Guide is, how the FGDG will be structured, explain the types of questions that will be asked (they are usually open-ended questions), explain the number of members that each FGD will have, explain how long each FGD will last, explain the composition of each FGD, whether the moderator will be the researcher or an appointed research assistant and how many FGDs will be conducted.
Note that;
This section is therefore supposed to enable the reader to understand all the questions of; Who, Why, When, How and Where about your Focus group Discussion Guide.
Experimental Checklist
In case the researcher chose experiment as the data collection method, then the data collection instrument will be the experimental checklist.
An experimental checklist therefore refers to a list of all the relevant scientific procedures that the researcher has to undertake while collecting data about the dependent and independent variables during an experiment.
Quality control methods/ pre-testing
This section can as well be referred to as validity and reliability. It's usually subdivided into two subsection validity and Reliability. The researcher is supposed to use this section to briefly but clearly explain how s/he will test for the validity and reliability of the research instruments.
Validity
Validity refers to the extent to which research instrument correctly measures what the researcher wants to measure. Therefore validity is about credibility or trustworthiness or accuracy or correctness of the research instrument.
The researcher is therefore supposed to provide a brief meaning of validity. Explain how s/he will ensure validity of the instruments. If you are to pre-test ensure that you explain the category of respondents that you will consider for the pilot study and how you will select them. Explain how you will carry-out the pilot study, Explain how you will go about managing the findings of the pre-test, the lessons learnt out of the pre-test and how you will go about redesigning the data collection instrument (s) (just in case the pre-test results deem it necessary).
Reliability
Reliability basically refers to consistency of a research instrument. Therefore reliability of a research instrument can easily be defined as the ability of a research instrument to yield the same results once used repeatedly over a given period of time while measuring the same variable(s).
The researcher is therefore supposed to provide a brief description of reliability. Explain how s/he will ensure reliability of the instrument(s). If you are to pilot test ensure that you explain the category of respondents that you will consider for the pilot study and how you will select them.
Explain how you will carry-out the pilot study, Explain how you will go about managing the findings of the pilot study, the lessons learnt out of the pilot and how you will go about redesigning the data collection instrument (s) (just in case the pilot results deem it necessary).
Note that:
An instrument can easily be reliable without being valid hence the need for testing for both validity and reliability.
A simple example of a reliable but invalid instrument would be offering a test to students and they averagely score 40% in the first sitting, they again score averagely 40% in the 2nd and 3rd sittings but yet the 40% is due to some wrongly set questions, which do note enable these students to excel and score 90's. In this case the instrument is reliable because it consistently provides the same results but invalid because it's not actually measuring what the researcher intended to measure (It's not correct).
Therefore researchers must always pre-test for both validity (correctness) and Reliability (consistency).
Research (Data Collection) Instruments/Tools
The key tools utilized for data collection include:
- Interview Guides: Structured sets of questions or topics designed to guide an interviewer during face-to-face or key informant interviews.
- Self-administered Questionnaires: Questionnaires designed for respondents to complete independently, without direct interaction with an interviewer.
- Key Informant Guides: Structured outlines or questions used when interviewing key informants, individuals with specialized knowledge or experience relevant to the research.
- Group Discussion Topics: Specific subjects or issues designated for exploration during a focus group discussion to stimulate conversation and elicit diverse perspectives.
- Observation Checklist/Schedule: A systematic list or plan used by researchers to observe and record specific behaviors, events, or characteristics during the observation method.
- Library Search: A systematic exploration of existing literature and information sources within a library to gather relevant data for research.
- Tests: Structured assessments or examinations conducted to measure specific abilities, knowledge, or characteristics of individuals.
- Use of Diary: The recording of regular, chronological entries detailing events, behaviors, or experiences over time, serving as a method of data collection in research.
The selection of the data collection method is guided by:
- Accuracy of Information: The degree to which the chosen data collection method ensures precise, reliable, and truthful information from the participants, influencing the method’s appropriateness for the research.
- Practical Considerations: Factors such as time, available resources, equipment, and personnel, which impact the feasibility and suitability of a particular data collection method for the research.
- Response Rate of Respondents: The anticipated level of participation and willingness of the target respondents to engage with the chosen data collection method, affecting the method’s effectiveness in gathering sufficient and representative data.
- Geographical Area Coverage: The extent to which the selected data collection method can efficiently collect information across the intended geographical area, considering the distribution and accessibility of the target population.
Characteristics of a Good Research Instrument
- The Instrument must be valid and reliable
- It must be based upon the Conceptual framework.
- It must gather data suitable for and relevant to the research topic.
- It must gather data would test the hypotheses or answer the questions under investigation
- It should be free from all kinds of bias.
- It must contain clear and definite directions to accomplish it.
- It must be accompanied by a good cover letter.
- It must be accompanied, if possible, by a letter of recommendation from a sponsor/school.
Advantages and Disadvantages of Common Research Instruments/Tools
1. Questionnaire/Questionnaire survey
The researcher is supposed to briefly describe this method of data collection, provide a justification for choosing this method of data collection, explain the type of data he/she expects to collect while using this method, the type of instrument that will support this data collection method and as well which category of the population will be subject to this data collection method.
A questionnaire survey is a data collection method mainly aimed towards collecting quantitative data where the researcher designs a set of questions related to the study objectives for purpose of collecting the required data.
Main types of questionnaires include:
- Mail questionnaires: This is a form of questionnaire that is prepared and mailed out to the respondent who must be part of the selected sample from a given study population. The main purpose of using a mailed questionnaire is to ensure that the researcher connects with a wider range of respondents. Basic forms of mails include; The E-mail, postal mails and Drop box survey mails among others.
- Self-administered questionnaire: This is a form of questionnaire where the respondent is left to read the questions, then fills in the answers by him/herself. This questionnaire is however sometimes filled in the presence of the interviewer(s) who usually stand-by to provide any form of support in case the respondent deems it necessary.
- Directly administered questionnaires: This is a form of questionnaire where the interviewer him/herself supports the respondent to fill the questionnaire. In this case the interviewer may keep reading questions for the respondent to answer. The interviewer can therefore support the respondent by rephrasing questions for a better understanding but without compromising the quality of the question. The main disadvantage of such a method is that it can easily lead to interviewer bias.
- Web-based questionnaires: This method is sometimes confused with mail questionnaires, however there is a difference between the two as this method is purely through use of web-site links while as mail questionnaire may be postal or email or even hand delivered mails by an agent of the researcher. Web-based questionnaire is becoming so inevitably growing where organizations (Private and Public), Groups and individuals, use internet based questionnaire surveys. This method is so cost effective and quicker but as well less detailed as compared to the other methods. Though its biggest challenge is the fact that it requires the use of internet and computer or high level technology which some potential respondents may not readily have access to, hence a strong limitation.
Types of questions asked include:
- Open-ended questions: This refers to a questionnaire which has questions that provide the respondent an opportunity to freely say whatever they deem necessary about the researcher's study or research question. Open-ended questions encourage full and meaningful participation of the respondent through motivating the interviewee to use his/her own knowledge about the subject. Open-ended questions usually help in the collection of qualitative data.
- Closed-ended questions: This refers to a questionnaire in which the questions asked have fixed responses that are provided for the respondent to choose from. These questions can be answered by simply ticking Yes or No (Boolean response). They can be answered through use of a Likert scale for example by selecting 5= Strongly Agree, 4 = Agree, 3 = Not Sure, 2 = Disagree and 1 = Strongly Disagree. The respondent is restricted and does not have the ability to exploit his knowledge to the fullest. Closed-ended questions usually help in the collection of quantitative data.
- Mixed questions: This is a triangulation of both Closed-ended and Open-ended questions in the same questionnaire. This is the most commonly used type of questionnaire and it helps in the collection of both qualitative and quantitative data. This method is mainly used in social research.
- Pictorial questions: This refers to a questionnaire where the researcher decides to use pictures to promote the interest in answering questions. In this case respondents will select their pictures of preference. This method is rarely used but it as well helps in collecting data just like the previous methods. This method is usually used in studies related to the prejudices in children and as well as in other form of social attitudes.
Forms of questionnaire structuring
- Structured Questionnaire: This is a form of questionnaire in which a specific set of predetermined questions were prepared by the interviewer in advance. This is the commonly used method by academic researchers.
- Unstructured Questionnaire: This is a form of questionnaire in which the survey questions to be asked the respondents are usually not set in advance.
Advantages:
- Easy administration to respondents across large areas.
- Respondents can answer at their own convenience.
- Quick data collection, saving time.
- Enhances anonymity, allowing respondents to freely address sensitive questions.
- Eliminates interview bias.
- Hard to design but easy to use.
Disadvantages:
- Unsuitable for illiterate respondents.
- Risk of misinterpretation of questions.
- Lack of opportunity for researcher probing.
- Low response rates.
- No observation of facial expressions.
- Inflexible tool in terms of respondent approach.
How to Construct a Questionnaire:
- Keep it brief and attractive.
- Begin with simple questions, ensuring logical sequencing.
- Include researcher’s address and a clear title.
- Provide an introduction, emphasizing the study’s significance, confidentiality, and instructions.
- Use simple language, avoiding technical terms.
- Ask specific questions related to research objectives.
- Avoid leading and double questions.
- Place sensitive questions at the end.
- Include a variety of question types.
2. Interview Instrument (Interview Guide/Schedule)
The researcher is supposed to briefly describe this method of data collection, provide a brief justification for choosing this method of data collection, describe which type of data is expected to be collected using this method, which instrument will support this data collection method and the category of the study population to which this method will be applied.
Interviewing is a method of data collection that involves verbal or non-verbal exchanges between an interviewer(s) and an interviewee(s) where the interviewer asks questions related to the study objective(s) and the interviewee provides suitable responses based on his knowledge and experience.
Interviewing is the most commonly used method of data collection in social sciences, it's therefore close to impossible to conduct a social science research without using interviews as a method of data collection. Interviews are usually used by researchers to find out the attitudes and perceptions of the informants about certain study variables.
Types of interviews
While planning to collect data, a researcher who has chosen to use interviewing as one of the data collection methods should as well plan for the specific type of interview he/ she will adopt.
There are 3 basic forms of interviews, these include;
- Structured interviews: This is a form of interview where the researcher sets the interview questions in advance, ensures that they are precise and quantified answers/responses are needed. In this form of interview, questions must be asked in a standard way and the researcher ensures that most or all questions are asked. Usually the researcher sets possible answers for the interview, most questions have pre-set responses to be chosen from.
- Unstructured / In-depth Interviews: This is a form of interview where the researcher does not set any standard questions for the interview but rather starts up a conversation with an informant on a given topic and then follows the informant to ensure that he/she establishes what is important to discuss or not. In most cases the researcher may start-up the interview with a few open-ended questions but most of the questions asked during the interview will be emerging issues as a result of the interaction between the interviewer and the interviewee. During this kind of interview, as an interviewer; always ensure that you speak minimally and give room to the interviewee to do most of the talking. This interview will help you as a researcher to do in-depth interviewing and subsequently generate sensitive information.
- Semi-structural interviews: This is a form of interviewing usually used where the researcher is interested in collecting both qualitative and quantitative data. Therefore the researcher will have both standard questions (where the researcher expects predetermined responses) and open-ended questions (where the respondent is free to say whatever they have to say about a given topic). Therefore semi-structured interviews are simply a triangulation of structured and unstructured interviews.
Administering of interviews
This refers to how the researcher executes the interview. In most cases researchers may use; Telephone interviewing, Face-to-Face interviewing or group interviewing among others. This choice greatly depends on the researchers interests.
Forms of Interview Administration
- Directly personal interviews: This is sometimes referred to as face-to-face interviews or one-on-one interviews. This is where the interviewer chooses to personally interact with one informant (interviewee) at ago.
- Telephone interview: This is an indirect form of personal interview where the researcher (interviewer) interacts with the interviewee through a telephone conversation. The interviewer will not have the capacity to read the body language of the interviewee. This method can also take the trend of a single interviewer against multiple interviewees, commonly done through conferencing.
Note that:
- Telephone interviewing can easily be interrupted by technological breakdown.
- If well managed this method can support the researcher to collect information in the shortest time possible.
- Panel interview: This is a form of interview where a group of interviewers normally ask one interviewee (informant) a set of questions. This form of interview is usually a face -to - face or using modern conferencing technology. A Common example is a job interview where one respondent (interviewee) faces a panel of interviewers.
- Group interview: This is a form of interviewing where more than one interviewer interacts with more than one interviewee and all interviewers expect responses from the interviewees.
- Video conferencing interviews / internet interviews: This form of interviewing involves the interviewer (researcher) adopting modern technology supported with the use of internet to ensure that he/she directly contacts with his or her respondent (interviewees).
Note that; This is mainly through; Chart rooms and Video conferencing. It can be a one-to-one, one-to-many, many-to-one or many-to-many (interviewers) to-many (interviewees).
Considerations before an interview
These are issues that a researcher must reflect on before taking any form of interview; they include;
- Ensure that you are dressed neutrally (To guard against bias).
- Prepare to be friendly to the interviewee(s) but remain professional.
- Prepare not to talk academically (Avoid all technical jargons)
- Plan well and ensure that you are ready to ask more non-directional questions (non-leading questions or neutral questions).
- Prepare to avoid biased language
- Prepare probe questions. These will help you to conduct more in-depth interviews.
- Prepare a tape recorder (To capture the audio responses or recoding the informants responses).
- Prepare a note book.
- Prepare pen
- Prepare to take notes
- Prepare to be a moderate of the session by speaking less and let your interviewee speak more.
- Prepare to monitor the interview session i.e., so that it remains a relevant conversation about the study area, within a required time frame and with important issues being raised.
- Do a general preparation for the interview such as visiting the washroom before the process.
- Prepare the interviewee for the interview by greeting the interviewee, introducing yourself and making a brief suitable talk about the study while assuring the interviewee about confidentiality and motive of the study.
- Plan and prepare how you intend to close the interview. Don't forget to thank the informant for the time and resourceful information provided.
Advantages:
- Higher response rate.
- Suitable for non-literate respondents.
- Allows probing.
- Enables observation of respondent’s non-verbal cues.
- More control over data collection pace.
- Identity of respondent is known.
- Provides an opportunity for follow-up.
Disadvantages:
- Expensive and time-consuming, especially with a scattered population.
- Respondents may lack time for interviews.
- Prone to biases.
- Limited anonymity.
- Respondents may give pleasing answers.
- Embarrassing questions may hinder open responses.
- Difficulty in tracing respondents.
3. Observation Schedule/Checklist
The researcher is supposed to briefly describe this data collection method, provide a brief justification for choosing this method, describe the type of data he/she expects to collect using this method, the instrument that will support this method of data collection and the category of the study population to which this method will be applied.
Observation as a data collection method therefore refers to the process of the researcher regarding attentively or watching the actions, behaviors and code of conduct for a given population for purposes of making inferences.
The researcher may observe through;
- Tasting,
- Touching,
- Seeing or using his or her senses of sight,
- Smelling and as well as
- Hearing.
Forms of observation
There are three types of observation from which researchers may choose the most appropriate method for their study. These include;
- Non-participant observation: This is basically a form of observation techniques where the researcher keenly watches the subjects (elements) of the study population with their knowledge and consent but without being part of the situation being observed. Therefore, in this form of observation, the researcher will only concentrate on observing but not a participant. This method allows the researcher to focus fully on players and have little distraction since he/she is not an active participant hence complete and timely data collection. However, the main disadvantage of such a method is that subjects /elements being aware that they are being observed prompts them to behave differently.
- Participant observation: This is a form of observation where the researcher gets intensively involved with the study population in their natural environment but with a purpose of collecting data about the behaviors, attitudes and ways of living of a given cohort say religious or occupational groups. To avoid bias, the researchers are supposed to remain objective throughout the research process. Seek permission from relevant authorities but avoid informing a study population that it's under scrutiny since the main objective of the study is to penetrate the subjective worlds of those studied, and to generally see those worlds from the participants point of view. The researcher should avoid imposing his/her own views upon the research elements but rather remain objective enough to collect data that represents the true picture of the research subjects. As compared to non-participant observation, where subjects tend to behave differently because they are aware that they are being studied, in this case subjects are not aware that they are being studied and therefore remain natural; this supports the collection of relevant and valid information.
- Covert observation: This form of observation can as well be referred to as hidden observation or undercover observation. This is a form of observation where the researcher or observer is not known to the research subjects, the observer is usually out of sight or not revealed to the observed cohort.
For example;
- A lecturer may strategically plant a camera in a lecturer room to observe a given group of students.
- A parent may observe children over a given period of time; this could be behind a one-way glass.
- A researcher may secretly observe a given community over a given period of time.
Note that;
The main concern in this form of observation is the ethical issue of informed consent. Therefore, researchers must always find ways to go about this for example seeking for permission from relevant authorities, if it's a university you may seek the permission of management but not the students being observed.
While observing, the researcher should do the following;
- Ensure that you take notes
- Take photos of relevant scenarios
- Do video recordings.
- Do audio recordings.
- Sharpen your memory to capture important information until a point when you can actually record your information
Note that:
While undertaking the above, endeavor to be as private as possible mostly where the study subjects are not aware that they are being observed
Advantages:
- Oldest research method.
- Provides reliable, first-hand information.
- Enables coding and recording real-time behavior.
- Facilitates clarification of questions.
- Elicits a high response rate.
- Allows detailed information gathering using the senses.
Disadvantages:
- Risk of respondents putting on a show.
- Time-consuming.
- Expensive.
- Inability to observe past events.
- Influenced by observer weaknesses.
4. Tests
Used for educational research to assess achievement or intelligence quotient.
5. Focus Group Discussion (FGD)
The researcher is supposed to briefly describe the meaning of this method of data collection, provide a brief justification for choosing this method of data collection, describe which type of data is expected to be collected using this method, the instrument to be used and the category of the study population to which this method will be applied.
Focus Group Discussion is therefore a data collection method mainly for collection of qualitative data in which a manageable group of people of a given study population are carefully selected into a discussion guided by a moderator/ facilitator (researcher) to freely articulate their perceptions, attitudes, opinions, beliefs, ideas and experiences about a certain topic of interest.
Qualities of a good Focus Group Discussion;
- It must have a moderator who is knowledgeable
- The Focus Group (FG) must not be less than 6 (six) members and not more than 12 members.
- Members of the FG must share common characteristics which are relevant for the study. For example members may have similar levels of education, professions, Age group & Gender among others parameters.
- Members of the FG must be selected from the study population of interest or sampling frame.
- The FG must have guidelines to guide procedure.
- It must be focused to the study area of interest
- Members must be considered equally.
- The moderator must have a predetermined list of open-ended questions.
- The FG must rely on discussions among all participants rather than dominancy of the moderator and some "I know it all" members.
Remember that:
"Garbage-in- Garbage-Out"
implying that when you review substandard documents, your analysis will yield substandard findings, your inferences will be substandard and as well you will ultimately generate substandard
Functions of the moderator /Facilitator of a FGD;
- To introduce the purpose of the discussion to all members
- To start the session
- To encourage free participation by all members.
- To regulate behavior of all members and promote equity and equality
- To ensure that the discussion remains in line with the study topic
Note that:
Avoid using one of the members of the FG as a recorder The moderator/Researcher should come along with a rapporteur or secretary who is highly qualified to take minutes, record proceeding, take photos and as well as a video coverage).
Advantages:
- Gathers a variety of opinions.
- Reaches a large number in a short time.
- Encourages mutual checks among group members.
- Involves directly affected individuals.
- Provides comfort for those hesitant in larger groups.
Disadvantages:
- Lacks anonymity.
- Expensive and time-consuming.
- Sensitive matters may limit open discussion.
- Risk of dominance by one participant.
- Group influence may generate desirable ideas.
6. Telephone Survey
Advantages:
- Higher response rate than mail surveys.
- Time-efficient.
- Eliminates interviewer bias.
- Covers a broader geographical area.
- Offers comfort to shy respondents.
- Cost-effective and convenient.
- Allows probing during conversation.
Disadvantages:
- Excludes respondents without telephones.
- Difficulty in accessing phone numbers.
- Prone to human weaknesses.
7. Mail Survey
- Questionnaires mailed to respondents.
- Applicable for widespread geographical studies.
For additional advantages and disadvantages, refer to those of a questionnaire.
8. Diary Method
- Records events or occasions in a diary.
- Provides valuable data on individual work patterns.
9. Experiments
The researcher is supposed to briefly describe the meaning of this method of data collection, describe which type of data is expected to be collected using this method, provide a brief justification for choosing this method of data collection, the instrument of data collection that will be used specifically for this method and the category of the study population to which this method will be applied.
Experiments help the researcher to collect quantitative data. It's therefore, a scientific procedure of data collection where the researcher sets up two equivalent groups/cohorts (Treatment group and Control group) then randomly selects elements into the treatment and control groups and subjects the treatment to an intervention but leaves the control without the intervention and then closely monitors the changes.
Key issues to note;
- Subjects are randomly selected into each of the cohorts or there is randomization.
- There are two groups, a control where the intervention is not administered and a treatment where the intervention.
- There must be no external factors to influence cohorts.
- The researcher must closely monitor the two groups.
- The treatment and control groups must be equivalent.
- The treatment and control groups must not know each other and should not interact.
- There must be a specified period of time for the experiment
- There must be set guidelines to regulate the experiment.
Note that;
This is the most expensive data collection method but as well very accurate if well regulated. Experiments are usually used in medical or clinical research and usually at 99% to 99.9% level of significance with a margin of error of 0.01 to 0.001, the smaller the margin of error the better and more reliable the findings in a medical or clinical research
