Methods of Research – Observational Trials

Observational research (or field research) is a type of correlational (i.e., non-experimental) research in which a researcher observes ongoing behavior.

Observational research is particularly prevalent in the social sciences and in marketing. It is a social research technique that involves the direct observation of phenomena in their natural setting. This differentiates it from experimental research in which a quasi-artificial environment is created to control for spurious factors, and where at least one of the variables is manipulated as part of the experiment. It is typically divided into naturalistic (or “nonparticipant”) observation, and participant observation. Cases studies and archival research are special types of observational research. Naturalistic (or nonparticipant) observation has no intervention by a researcher. It is simply studying behaviors that occur naturally in natural contexts, unlike the artificial environment of a controlled laboratory setting. Importantly, in naturalistic observation, there is no attempt to manipulate variables. It permits measuring what behavior is really like. However, its typical limitations consist in its incapability exploring the actual causes of behaviors, and the impossibility to determine if a given observation is truly representative of what normally occurs.

In some cases, rather than following a group of people from a specific point in time onwards, the researchers take a retrospective approach, working backwards as it were. They might ask participants to tell them about their past behavior, diet or lifestyle (e.g. their alcohol consumption, how much exercise they did, whether they smoked etc.) They might also ask for permission to consult the participants’ medical records (a chart review). This is not always a reliable method and may be problematic as some people may forget, exaggerate or idealize their behavior. For this reason, a prospective study is generally preferred if feasible although a retrospective pilot study preceding a prospective study may be helpful in focusing the study question and clarifying the hypothesis and feasibility of the latter (Hess, 2004).

Fig 1:

Different types of observational methods and distinctions need to be made between:

  • Controlled Observations
  • Natural Observations
  • Participant Observations

Controlled Observation

Controlled observations (usually a structured observation) are likely to be carried out in a psychology laboratory. The researcher decides where the observation will take place, at what time, with which participants, in what circumstances and uses a standardized procedure. Participants are randomly allocated to each independent variable group.

Rather than writing a detailed description of all behavior observed, it is often easier to code behavior according to a previously agreed scale using a behavior schedule (i.e. conducting a structured observation).

The researcher systematically classifies the behavior they observe into distinct categories. Coding might involve numbers or letters to describe a characteristics, or use of a scale to measure behavior intensity. The categories on the schedule are coded so that the data collected can be easily counted and turned into statistics.


1. Controlled observations can be easily replicated by other researchers by using the same observation schedule. This means it is easy to test for reliability.

2. The data obtained from structured observations is easier and quicker to analyze as it is quantitative (i.e. numerical) – making this a less time consuming method compared to naturalistic observations.

3. Controlled observations are fairly quick to conduct which means that many observations can take place within a short amount of time. This means a large sample can be obtained resulting in the findings being representative and having the ability to be generalized to a large population..


1. Controlled observations can lack validity due to the Hawthorne effect/demand characteristics. When participants know they are being watched they may act differently.

Naturalistic Observation

Naturalistic observation (i.e. unstructured observation) involves studying the spontaneous behavior of participants in natural surroundings. The researcher simply records what they see in whatever way they can.

Compared with controlled/structured methods it is like the difference between studying wild animals in a zoo and studying them in their natural habitat.

With regard to human subjects Margaret Mead used this method to research the way of life of different tribes living on islands in the South Pacific. Kathy Sylva used it to study children at play by observing their behavior in a playgroup in Oxfordshire.


1 By being able to observe the flow of behavior in its own setting studies have greater ecological validity.

2. Like case studies naturalistic observation is often used to generate new ideas. Because it gives the researcher the opportunity to study the total situation it often suggests avenues of enquiry not thought of before.


1. These observations are often conducted on a micro (small) scale and may lack a representative sample (biased in relation to age, gender, social class or ethnicity). This may result in the findings lacking the ability to be generalized to wider society.

2. Natural observations are less reliable as other variables cannot be controlled. This makes it difficult for another researcher to repeat the study in exactly the same way.

3. A further disadvantage is that the researcher needs to be trained to be able to recognize aspects of a situation that are psychologically significant and worth further attention.

4. With observations we do not have manipulations of variables (or control over extraneous variables) which means cause and effect relationships cannot be established.

Participant Observation

Participant observation is a variant of the above (natural observations) but here the researcher joins in and becomes part of the group they are studying to get a deeper insight into their lives. If it were research on animals we would now not only be studying them in their natural habitat but be living alongside them as well!

This approach was used by Leon Festinger in a famous study into a religious cult who believed that the end of the world was about to occur. He joined the cult and studied how they reacted when the prophecy did not come true.

Participant observations can be either cover or overt. Covert is where the study is carried out ‘under cover’. The researcher’s real identity and purpose are kept concealed from the group being studied.

The researcher takes a false identity and role, usually posing as a genuine member of the group. On the other hand, overt is where the researcher reveals his or her true identity and purpose to the group and asks permission to observe.


1. It can be difficult to get time / privacy for recording. For example, with covert observations researchers can’t take notes openly as this would blow their cover. This means they have to wait until they are alone and reply on their memory. This is a problem as they may forget details and are unlikely to remember direct quotations.

2. If the researcher becomes too involved they may lose objectivity and become bias. There is always the danger that we will “see” what we expect (or want) to see. This is a problem as they could selectively report information instead of noting everything they observe. Thus reducing the validity of their data.

Types of observational studies

  • Case-control study: study originally developed in epidemiology, in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.
    • Porta’s Dictionary of Epidemiology defines the case-control study as: an observational epidemiological study of persons with the disease (or another outcome variable) of interest and a suitable control group of persons without the disease (comparison group, reference group). The potential relationship of a suspected risk factor or an attribute to the disease is examined by comparing the diseased and nondiseased subjects with regard to how frequently the factor or attribute is present (or, if quantitative, the levels of the attribute) in each of the groups (diseased and nondiseased).”
    • For example, in a study trying to show that people who smoke (the attribute) are more likely to be diagnosed with lung cancer (the outcome), the cases would be persons with lung cancer, the controls would be persons without lung cancer (not necessarily healthy), and some of each group would be smokers. If a larger proportion of the cases smoke than the controls, that suggests, but does not conclusively show, that the hypothesis is valid.
    • The case-control study is frequently contrasted with cohort studies, wherein exposed and unexposed subjects are observed until they develop an outcome of interest
  • Cross-sectional study: involves data collection from a population, or a representative subset, at one specific point in time.
    • They are often used to assess the prevalence of acute or chronic conditions, or to answer questions about the causes of disease or the results of intervention. They may also be described as censuses. Cross-sectional studies may involve special data collection, including questions about the past, but they often rely on data originally collected for other purposes. They are moderately expensive, and are not suitable for the study of rare diseases. Difficulty in recalling past events may also contribute bias.
  • Longitudinal study: Correlational research study that involves repeated observations of the same variables over long periods of time.
    • Longitudinal studies allow social scientists to distinguish short from longterm phenomena, such as poverty. If the poverty rate is 10% at a point in time, this may mean that 10% of the population are always poor or that the whole population experiences poverty for 10% of the time. It is impossible to conclude which of these possibilities is the case by using one-off cross-sectional studies.
    • Types of longitudinal studies include panel studies and cohort studies. Cohort studies sample a cohort, defined as a group experiencing some event (typically birth) in a selected time period, performing a cross-section at intervals through time. Panel studies also use cross-sectional data and compare the same group of individuals at intervals through time, but the sample is not necessarily a cohort, as it can be a group of people that do not share a common event. Therefore, a cohort study can be considered a panel study, but a panel study is not always a cohort study.
    • A retrospective study is a longitudinal study that looks back in time. For instance, a researcher may look up the medical records of previous years to look for a trend.
  • Cohort study or Panel study: a particular form of longitudinal study where a group of patients is closely monitored over a span of time.
    • A cohort is a group of people who share a common characteristic or experience within a defined period (e.g., are born, are exposed to a drug or vaccine or pollutant, or undergo a certain medical procedure). Thus a group of people who were born on a day or in a particular period, say 1948, form a birth cohort. The comparison group may be the general population from which the cohort is drawn, or it may be another cohort of persons thought to have had little or no exposure to the substance under investigation, but otherwise similar. Alternatively, subgroups within the cohort may be compared with each other.
    • Randomized controlled trials (RCTs) are a superior methodology in the hierarchy of evidence in therapy, because they limit the potential for any biases by randomly assigning one patient pool to an intervention and another patient pool to non-intervention (or placebo). This minimizes the chance that the incidence of confounding (particularly unknown confounding) variables will differ between the two groups. However, it is important to note that RCTs may not be suitable in all cases and other methodologies could be much more suitable to investigate the study’s objective(s).
    • Cohort studies can either be conducted prospectively, or retrospectively from archived records
  • Ecological study: an observational study in which at least one variable is measured at the group level.
    • Ecological studies are studies of risk-modifying factors on health or other outcomes based on populations defined either geographically or temporally. Both risk-modifying factors and outcomes are averaged for the populations in each geographical or temporal unit and then compared using standard statistical methods.
    • Ecological studies have often found links between risk-modifying factors and health outcomes well in advance of other epidemiological or laboratory approaches.
    • Notable examples
      • Cholera study
      • Diet and cancer
      • UV radiation and cancer
      • Diet and Alzheimer’s
      • UV radiation and influenza

Recording of Data

With all observation studies an important decision the researcher has to make is how to classify and record the data. Usually this will involve a method of sampling. The three main sampling methods are:

  • Event sampling. The observer decides in advance what types of behavior (events) she is interested in and records all occurrences. All other types of behavior are ignored.
  • Time sampling. The observer decides in advance that observation will take place only during specified time periods (e.g. 10 minutes every hour, 1 hour per day) and records the occurrence of the specified behavior during that period only.
  • Instantaneous (target time) sampling. The observer decides in advance the pre-selected moments when observation will take place and records what is happening at that instant. Everything happening before or after is ignored.

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