Tusla - Ireland's Child & Family Agency

Research Tools



Glossary of Research Terms and Methodologies





A brief summary of the study and its results. It should tell you what the study tried to show, how    the researchers went about it, and what they found.                                                                               


An incident which resulted in harm experienced by a research participant engaging in a research study.


A researcher undertaking the scientific and ethical responsibility for a study, either on his/her own behalf or on behalf of a research team or organisation, seeking a decision from a Research Ethics Committee through formal application.


A favourable consequence arising from a study for the participants involved, for organisations and to the wider public.


Influences that distort the results of a research study.


is an international research network that produces systematic reviews of the effects of social interventions in Crime & Justice, Education, International Development and Social Welfare.


is the extent to which an intervention (whether a treatment, procedure or service) improves the outcome for patients in practice.  It is also known simply as ‘effectiveness’. See also: Randomised Controlled Trial


An international organisation that aims to help people make well informed decisions about health care by preparing, maintaining, and ensuring the accessibility of systematic reviews of healthcare interventions                                                                                                           


A community is a group of people understood as having a certain identity due to the sharing of common interests, experiences, heritage or to a shared proximity. This includes identified social, cultural, ethnic or religious groups.


A conflict of interest arises when a member (or members) of a Research Ethics Committee holds interests with respect to specific applications for review that may jeopardise his/her ability to provide a free and independent evaluation of the research focused on the protection of the research participants. This includes actual and perceived conflicts of interest. Conflicts of interest may arise when a REC member has financial, material, institutional or social ties to the research which must be declared.

CONSORT (Consolidated Standards of Reporting Trials)

is a set of guidelines for how trials should be reported, which include giving a flow diagram of how participants are recruited, randomised and followed up.                                                                                                


Reviewing a study to judge the quality of the method used and the reliability of the conclusions.


The response by a Research Ethics Committee to an applicant following the review of the application in which the Research Ethics Committee’s position on the ethical validity of the proposed research is stated.


Guidance documentation that assists with decisions relating to the responsibility to adhere to established and relevant standards of ethical principles and practice.


Pandya-Wood et al (2017) defines ethics as the “the rules of conduct and moral principles recognized in respect to a class of human actions or a group, culture, etc.”


Review of proposed research by the Research Ethics Committee Chair and Vice-Chair, rather than by the entire Research Ethics Committee.


The General Data Protection Regulation (GDPR) replaces the existing data protection framework under the EU Data Protection Directive. It outlines the enhanced rights and responsibilities which must be complied with under the new legislation the Data Protection Act 2018, which was ratified on 24th May 2018.


The degree of dissimilarity among cases with respect to a particular characteristic.


A term used in meta-analyses and systematic reviews to indicate that the results of studies are similar; the opposite of heterogeneity. Study results are also regarded as homogeneous if any differences could have occurred by chance.


A research study conducted according to a single proposal but at more than one site, and therefore, may be carried out by more than one Applicant.


This hypothesis states that there is no difference between groups. The alternative hypothesis states that there is some real difference between two or more groups.


The process by which children and young people have active involvement and real influence in decision-making on matters affecting their lives, both directly and indirectly.


A structured approach for developing review questions that divides each question into 4 components: the population (the population being studied); the interventions (what is being done); the comparators (other main treatment options); and the outcomes (measures of how effective the interventions have been).


Primary study ‘Original research’ in which data are collected. The term primary study is sometimes used to distinguish it from a secondary study (re-analysis of previously collected data), meta-analysis, and other ways of combining studies (such as economic analysis and decision analysis).


A researcher who undertakes scientific and ethical responsibility, either on his/her own behalf or on behalf of an organisation, for the scientific and ethical integrity of a research study at a specific site or group of sites. In some instances, a coordinating investigator may be appointed as the responsible leader of a team of sub-investigators.


By patient and public in this context we mean everyone; children and young people, those attending Tusla services including potential users of services. We also include parents, carers, guardians, staff members or anyone involved in the care and protection of children and young people.

By ‘involvement’ we mean the active involvement between children and young people/people who use services/parent/guardians/carers/staff/the general public and researchers. It does not include the use of people as participants in research (or as research ‘subjects’) and does not generate data for individual research projects.


Publication bias occurs when researchers publish the results of studies showing that a treatment works well and do not publish those results showing it did not have any effect. If this happens, analysis of the published results will not give an accurate idea of how well the treatment works. This type of bias can be assessed by a funnel plot.


Purposive sampling is the selection of participants who have knowledge or experience of the area being investigated.


A study in which a number of similar people are randomly assigned to 2 (or more) groups to test a specific drug, treatment or other intervention. One group (the experimental group) has the intervention being tested, the other (the comparison or control group) has an alternative intervention, a dummy intervention (placebo) or no intervention at all. The groups are followed up to see how effective the experimental intervention was. Outcomes are measured at specific times and any difference in response between the groups is assessed statistically. This method is also used to reduce bias.


In the context of decisions, requirements are constraining elements that express ethical considerations that the Research Ethics Committee requires or views as obligatory in pursuing the research.


Pandya-Wood et al (2017) refers to research ethics [as] “the moral principles guiding research from its inception through to completion and publication of results” which can also be defined as the “fostering of research that protects the interests of the public” and includes research participants and the researchers themselves”.


An independent body constituted of professionals, experts and lay people, whose responsibility it is to safeguard the welfare and the rights of research participants engaging in research studies, taking into account the scientific procedures and the concerns of the local community.


A research participant is an individual who participates in a research study.


A document that provides the background, rationale and objective(s) of a research study and describes its design, methodology and organisation, including ethical and statistical considerations.  Some of these consideration may be provided in additional documentation referred to in the proposal.


A clear statement in the form of a question of the specific issue that a researcher wishes to answer using data from one or more sources. Examples include: Do children who attend center-based early care and education programs have stronger academic and social skills than children who are cared for in a home-based child care setting? Does the Black-White achievement gap narrow or widen as children move through the elementary school grades?


A summary of the evidence in a number of different individual studies, with conclusions about their findings. A review may or may not be systematically researched and developed.


A study of studies: a review of individual studies (each of which is called a primary study). A systematic review is a secondary study.


A means of exploring uncertainty in the results of economic evaluations. There may be uncertainty because data are missing, estimates are imprecise or there is controversy about methodology. Sensitivity analysis can also be used to see how applicable results are to other settings. The analysis is repeated using different assumptions to examine the effect of these assumptions on the results.


An individual or organisation that takes on the scientific and ethical responsibility for the initiation, management, and/or financing of a research study.


A review that summarises the evidence on a clearly formulated review question according to a predefined protocol, using systematic and explicit methods to identify, select and appraise relevant studies, and to extract, analyse, collate and report their findings. It may or may not use statistical techniques, such as meta-analysis.


Transferability means that the research findings can be transferred from one context to similar situations or participants.


Whether a test or study actually measures what it aims to measure. Internal validity shows whether a study or test is appropriate for the question, for example, whether a study of exercise among gym members measures the amount of exercise people do at the gym, not simply whether people join. External validity is the degree to which the results of a study hold true in non-study situations, for example, in routine NHS practice. It may also be referred to as the generalisability of study results to non-study populations. For example, the external validity of a study that took place in Spain may be questioned if the results were to be applied to people in Australia.





Research that generates numerical data or data that can be converted into numbers. An example is research using clinical trials. Another example is the Census of England and Wales, which counts people and households. It might involve questions such as 'How many people visit their GP each year?' or 'What proportion of children have had this vaccine?'.


A total created from smaller units; the population of a county is an aggregate of the populations of the cities, rural areas, etc. that comprise the county.


A group of people sharing a common demographic experience who are observed through time. For example, all the people born in the same year constitute a birth cohort. All the people married in the same year constitute a marriage cohort.     


A range of estimated values that is the best guess as to the true population's value. Confidence intervals are usually calculated for the sample mean. In behavioural research, the acceptable level of confidence is usually 95%. Statistically, this means that if 100 random samples were drawn from a population and confidence intervals were calculated for the mean of each of the samples, 95 of the confidence intervals would contain the population's mean. For example, a 95% confidence interval for IQ of 95 to 105, indicates with 95% certainty that the actual average IQ in the population lies between 95 and 105.                                       


A crossover design (also called switch over or change over design) is a type of experimental design in which each research subject receives a sequence of experimental treatments over a number of time periods. A major advantage of the crossover design is that each subject serves as his or her own control. They often require a smaller number of participants than more traditional Randomized Control Trial designs.                                       


Fixed Effects Regression techniques that can be used to eliminate biases associated with the omission of unmeasured characteristics. Biases are eliminated by including an individual-specific intercept term for all cases.                                                       


A visual way of showing how the results of several studies of the same treatment vary. Usually the effect of treatment in each study is plotted on a graph against the number of people involved. Ideally, the points fall into an inverted funnel shape. If they do not, publication bias or other problems are likely.                                                                      


Statistical tests to determine whether a hypothesis is accepted or rejected. In hypothesis testing, two hypotheses are used: the null hypothesis and the alternative hypothesis. The alternative hypothesis is the hypothesis of interest; it generally states that there is a relationship between two variables. The null hypothesis states the opposite, that there is no relationship between two variables.                                                             


Maximum-likelihood estimation (MLE) is one of the most widely used methods for estimating the parameters of a statistical model (for example, means and variances) from sample data. Using the sample data, MLE obtains estimates of the population parameters such that the probability (likelihood) of obtaining the observed data is maximized. 


A statistical technique that combines and analyses data across multiple studies on a topic. In early childhood and education research, a meta-analysis combines a number of studies (usually conducted by a number of different researchers in a variety of contexts) to quantify the effect a given independent or treatment variable (e.g., full-day versus part-day kindergarten and class size) has on a given outcome (e.g., children's academic skills and prevalence of positive and negative classroom behaviour).                                                        


The average number of patients who need to receive the treatment or other intervention for one of them to get the positive outcome in the time specified. The closer the NNT is to 1, the more effective the treatment.                                                                                    


Compares the odds (probability) of something happening in 1 group with the odds of it happening in another. An odds ratio of 1 shows that the odds of the event happening (for example, a person developing a disease or a treatment working) is the same for both groups. An odds ratio of greater than 1 means that the event is more likely in the first group than the second. An odds ratio of less than 1 means that the event is less likely in the first group than in the second group.


A fake (or dummy) treatment given to patients in the control group of a clinical trial. It is indistinguishable from the actual treatment (which is given to patients in the experimental group). The aim is to determine what effect the experimental treatment has had - over and above any placebo effect caused because someone has had (or thinks they have had) care or attention.


The probability that the results of a statistical test were due to chance. A p-value greater than .05 is usually interpreted to mean that the results were not statistically significant. Sometimes researchers use a p-value of .01 or a p-value of .10 to indicate whether a result is statistically significant. The lower the p-value the more rigorous the criteria for concluding significance.


A measure of the state of health of a person or group in which the benefits, in terms of length of life, are adjusted to reflect the quality of life. One QALY is equal to 1 year of life in perfect health.

QALYs are calculated by estimating the years of life remaining for a patient following a particular treatment or intervention and weighting each year with a quality-of-life score (on a 0 to 1 scale). It is often measured in terms of the person’s ability to carry out the activities of daily life, and freedom from pain and mental disturbance.                                        


According to the DCYA’s guidance (2012: 2) ‘one of the main concerns in research ethics is the protection of participants from harm or the limitation of risk of harm.  Risk refers to potential harm (physical, psychological or social) that may arise from the research.  Research could result in different types of harm, for example, mental distress or the stigmatising of certain social, cultural, racial or religious groups’.  Degrees of risk may vary for participants. Applicants must assess and put in adequate protection measures to mitigate against potential harm to research participants. 


The process of selecting a subgroup of a population (i.e. sample) that will be used to represent the entire population.                                           


Theoretical sampling can be defined as a process of data collection for generating theory where the analyst jointly collects, codes and analyses his data and decides what data to collect next and where to find them in order to develop his theory as it emerges.                                              


Secondary data analysis is the analysis of data that was collected by someone else


Statistical analysis is the process of collecting, examining, manipulating, summarizing and interpreting quantitative or numerical data for the purpose of identifying patterns, trends, and relationships in the data. It can include the use of descriptive statistics such as percentages, means, variances and correlations and/or the use of inferential statistics such as t-tests, chi-square tests, regression, and analysis of variance (ANOVA). 


A 'snapshot' observation of a set of people at 1 time. This type of study contrasts with a longitudinal study, which follows a set of people over a period of time. 


A study of the same group of people at different times. This contrasts with a cross-sectional study, which observes a group of people at a point in time.                         


Research that generates numerical data or data that can be converted into numbers. An example is research using clinical trials. Another example is the Census of England and Wales, which counts people and households. It might involve questions such as 'How many people visit their GP each year?' or 'What proportion of children have had this vaccine?'.


Survival curve is a curve that starts at 100% of the study population and shows the percentage of the population still surviving at successive time intervals.



Qualitative research uses individual in-depth interviews, focus groups or questionnaires to collect, analyse and interpret data on what people do and say. It reports on ;the ;meanings, concepts, definitions, characteristics, metaphors, symbols and descriptions of things. It is often exploratory and open ended.

A field of social research that is carried out in naturalistic settings and generates data largely through observations and interviews. Compared to quantitative research, which is principally concerned with making inferences from randomly selected samples to a larger population, qualitative research is primarily focused on describing small samples in non-statistical ways.


An epidemiological study that is used to identify risk factors for a medical condition. This type of study compares a group of patients who have that condition with a group of patients    who do not have it and looks back in time to see how the characteristics of the two groups differ. 


A case study is an in-depth study of a particular research problem rather than a sweeping statistical survey or comprehensive comparative inquiry. It is often used to narrow down a very broad field of research into one or a few easily researchable examples. The case study research design is also useful for testing whether a specific theory and model actually applies to phenomena in the real world. It is a useful design when not much is known about an issue or phenomenon.

An intensive investigation of the current and past behaviours and experiences of a single person, family, group, or organization.                                   

in depth analysis and systematic description of one patient or group of similar patients to promote a detailed understanding of their circumstances. 


An analysis that seeks to establish the cause and effect relationships between variables.


The quality of two or more objects that can be evaluated for their similarity and differences


A community is a group of people understood as having a certain identity due to the sharing of common interests, experiences, heritage or to a shared proximity. This includes identified social, cultural, ethnic or religious groups


A procedure for organizing narrative, qualitative data into themes and concepts.


Cross-cultural research most commonly involves comparison of some cultural trait (or relationships between traits) across a sample of societies.                       


Descriptive research designs help provide answers to the questions of who, what, when, where, and how associated with a particular research problem; a descriptive study cannot conclusively ascertain answers to why. Descriptive research is used to obtain information concerning the current status of the phenomena and to describe “what exists” with respect to variables or conditions in a situation.                                                           


A qualitative method for examining behaviour under specific circumstances. An EDM (Ethnographic Decision Model) is often referred to as a decision tree or flow chart and comprises a series of nested if-then statements that link criteria (and combinations of criteria) to the behaviour of interest.                                                                    


A qualitative method for examining behaviour under specific circumstances. An EDM is often referred to as a decision tree or flow chart and comprises a series of nested ‘if-then’ statements that link criteria (and combinations of criteria) to the behaviour of interest.


The use of scientific research methods to plan intervention programs, to monitor the implementation of new programs and the operation of existing programs, and to determine how effectively programs or clinical practices achieve their goals.


A research design used to establish cause-and-effect relationships between the independent and dependent variables by means of manipulation of variables, control and randomization. A true experiment involves the random allocation of participants to experimental and control groups, manipulation of the independent variable, and the introduction of a control group for comparison purposes. Participants are assessed after the manipulation of the independent variable in order to assess its effect on the dependent variable (the outcome).


Feasibility studies are used to determine whether an intervention is appropriate for further testing; in other words, they enable researchers to assess whether or not the ideas and findings can be shaped to be relevant and sustainable.     


Research conducted where research subjects live or where the activities of interest take place.


An interview conducted with a small group of people, all at one time, to explore ideas on a particular topic. The goal of a focus group is to uncover additional information through participants' exchange of ideas.


The development of social science theory from the inductive analysis of data. This approach is generally used in qualitative research. The specific and detailed observations in the data are studied and understood to such an extent that a theory of more general patterns of behaviour can be generated.


A psychological response in which participants change their behaviour simply because they are participants in a study, not because of the research treatment.


Implementation science is the study of methods to promote the integration of research findings and evidence into healthcare policy and practice. It seeks to understand the behaviour of healthcare professionals and other stakeholders as a key variable in the sustainable uptake, adoption, and implementation of evidence-based interventions.


A method of data collection in which the interviewer uses a pre-determined list of topics or questions to gather information from a respondent. The interviewer, however, may stray from the list to follow-up on things the respondent says during the interview.


An interview in which the researcher asks open-ended questions. The researcher aims to give respondents the latitude to talk freely on a topic and to influence the direction of the interview. There is no predetermined plan about the specific information to be gathered from these types of interviews.


A method of study that begins with specific observations and measures, from which patterns and regularities are detected. These patterns lead to the formulation of tentative hypotheses, and ultimately to the construction of general conclusions or theories.


This type of research design draws a conclusion by comparing subjects against a control group, in cases where the researcher has no control over the experiment. There are two general types of observational designs. In direct observations, people know that you are watching them. Unobtrusive measures involve any method for studying behaviour where individuals do not know they are being observed. An observational study allows a useful insight into a phenomenon and avoids the ethical and practical difficulties of setting up a large and cumbersome research project.


A field research method whereby the researcher develops knowledge of the composition of a particular setting or society by taking part in the everyday routines and rituals alongside its members. A principle goal of participant observation is to develop an understanding of a setting from a member’s perspective, which may be accomplished through both informal observations and conversations, as well as in-depth interviews.


Risk is the probability of an even happening divided by the all the probability of it happening or it not happening. (The risk of throwing a six with a die is ;1/6) Risk ratio (RR) is one measure of a treatment's clinical effectiveness. If it is equal to 1, then the effects of the treatment are no different from those of the control& treatment. If the RR is greater ;(or less) than 1, then the effects of the treatment are more (or less) than those of the control treatment. Note that the effects being measured may be adverse(e.g.death, disability)or desirable(e.g.stopping smoking).


In terms of ethics questions, assessing risk is not simply a procedural requirement – rather, you need to reflect on three key questions in relation to your planned project: • What is ‘harm’? • What is ‘risk’? • What are the potential benefits? There are risks, harms, costs and benefits that arise in social research, and these need to be assessed, for two reasons:

1. Assessments enable researchers, reviewers, and funders to decide whether the research is worth doing at all, and whether it could be made less risky.

2. Later these assessments help the people you are inviting to take part in your study make an informed decision. Informed consent is the legal means of transferring responsibility for risk-taking from the researcher to the participant.

It is useful to think about harm-benefit during the early stages of planning a study, when it is still fairly easy to redesign the study to reduce risks.


Social analysis is the evaluation of issues related to social characteristics, the general quality of life, social services and social justice of a society. The analysis touches on individuals, governments, economies, groups and environments. It studies the past with respect to the present, particularly large-scale developments such as urbanization, ethnic cultures, migration of people and identity formation.

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