Modes of Observation
Sampling is a technique used in research or study of a population through selecting subsets of the population according to one or more criteria. Two kinds of sampling techniques are probability sampling and non probability sampling.
(b) Probability sampling
The term describes a sampling in which the probability that an element will get included in a sample that is known. It enables researchers to make statistical generalizations to a larger population. Probability sampling methods are the sampling techniques that can get relied upon to approximate representative samples. Various specific types of probability samples are simple probability sample, equal probability of selection method, systematic sample and simple random sample (Maxfield & Babbie, 2014).
(c) Equal probability of selection method [EPSEM]
EPSEM is a technique of probability sampling in which all the members of the population have an equal chance to get selected in a sample to be representative of the population.
(d) Sample element
Sample element refers to the unit about which formation gets collected, and that offers the basis for analysis. Mostly in survey research elements are people and other types of units for criminal justice research is gangs, police beats, court cases and correctional facilities (Maxfield & Babbie, 2014).
(e) Sample statistic
Sample statistic refers to the summary description/characteristic of a particular a sample used to estimate a population parameter.
(f) Sampling distribution
Sampling distribution refers to the range of sample statistics that gets obtained when many samples get selected.
A population also known as universe refers to a naturally existing collection of a certain type of phenomenon that is under investigation (often referring to a group of individuals living in a designated geographic location at a given point in time). Simply, it describes the theoretically specified grouping of study elements.
(h) Population parameter
Population parameter defines the value of a given variable in a population.
(i) Sampling frame
A sampling frame refers to a complete list or quasi-list of all members of the population.
(j) Simple random sampling
Simple random sampling refers to a probability sampling technique in which the units that compose a population gets assigned numbers, a set of random numbers then get generated, and the units that have those numbers get included in the sample.
Stratification is the grouping of units composing a population into homogeneous groups (or strata) before sampling. The procedure gets used in conjunction with systematic, simple random or cluster sampling so as to enhance the representatives of a sample, at least regarding the stratification variables.
(l) Systematic sampling
Systematic sampling refers to an approach of probability sampling in which units are occurring in some specified interval in a list get selected for inclusion in the sample.
(m) Disproportionate stratified sampling
Disproportionate stratified sampling refers to the deliberate drawing of a sample that over-represents or under-represents some characteristic of a population. It gets done to ensure that a sufficient number of uncommon cases in the sample get obtained.
(n) Cluster sampling
Multistage cluster sampling is the sample design procedure that involves the initial sampling of groups of elements –clusters – followed by the selection of elements within each of the selected clusters.
(o) Non-probability sampling
Non-probability sampling is a procedure in which a sample gets selected in some manner other than those specified by probability theory. Non-probability sampling methods refer to sampling methods that cannot get trusted to be representative of some specified population. Examples of non-probability sampling include purposive, quota, and snowball sampling.
(p) Purposive sample
Purposive sample refers to a type of non probability sample that you select the units for observation by own judgment concerning the ones that will best suit a person’s research purpose.
(q) Quota sampling
Quota sampling refers to a non probability sample in which units get selected in the sample by pre specified characteristics so that the entire sample will have the same distribution of features as are assumed to exist in the population getting studied.
(r) Snowball sampling
Snowball sampling refers to a sampling technique for drawing a non probability sample in which research subjects get recruited and then asked to recruit additional subjects, or get interviewed and then requested to suggest additional interviewees. Snowball sampling techniques get frequently used on active criminals or deviants in criminal justice research.
Survey refers to an approach of collecting data by applying a standard instrument in a systematic manner to take measures from a large number of units.
Interview refers to a data-collection encounter in which an interviewer asks questions to a respondent (the interviewee). The session gets done on a face-to-face encounter or through a telephone call.
(u) Open-ended questions
Open-ended questions are survey questions that require the respondent to provide their answers in a blank space provided by the researcher.
(v) Close-ended questions
Closed-ended questions are survey questions that require a respondent to select an answer from a list provided by the researcher. They are easily analyzed compared to open-ended questions and offer greater uniformity of responses.
A questionnaire is a document that contains questions and other types of items designed to solicit information suitable for analysis.
(x) Computer-assisted interviewing [CAI]
Computer-assisted interviewing (CAI) is the use of computers to record answers keyed in by interviewers or by respondents themselves.
(y) Response rate
Response rate also known as completion rate is the number of persons participating in a survey divided by the number selected in the sample, in the form of a percentage. In self-administered surveys, it is the percentage of the questionnaires sent out that gets returned.
(z) Interview survey
Interview survey refers to the use of a questionnaire in a systematic way to interview a large number of people (respondents).
Question #2: Interview schedule
My name is Andrew Boss and a member of the state security monitoring committee, and would like to ask you a few questions concerning security in your locality. The information will get used by the committee in reviewing the work done by the law enforcement agencies. The interview should take about 5 minutes. Will you respond to the research?
- Which is your local area?
[PROBES: Where does the respondent come from?]
- How would you describe the general security of your locality?
[PROBES: How concerned is the respondent to criminal activity in their local area? What is the crime rate? How much does the respondent feel secure in their area? What are the common crimes in the local area?]
- Have you ever encountered a security issue? If yes, what happened?
[PROBES: Is the respondent a victim of a crime? What happened? When did that happen? Who were involved? How did you react to the situation? How did the law enforcement agencies handle the situation?]
- Would you describe the crime instances in your locality as conducted by criminal gangs in the area?
[PROBES: Does the respondent think that the crime activity is systematic and planned? Why?]
- How would you describe the response of the law enforcement agencies to crime in your local area?
[PROBES: How would you rate the response of the police to crime? How does the law enforcement handle crime?]
- What do you think could get done to enhance security in the locality?
[PROBES: What measures could get implemented to improve the safety? What comments do you have concerning security?]
I am grateful for the time you took for this interview. The information provided will assist greatly in enhancing the security of your area. Have a great day.
Maxfield, M., & Babbie, E. (2014): Research methods for criminal justice and criminology: Edition 7: Nelson Education.