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Nonexperimental research design

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Nonexperimental research design

  2. 2. INTRODUCTION…  Nonexperimental research design is one of the broad categories of research designs, in which the researcher observes the phenomena as they occur naturally, & no external variables are introduced.  It is a research design in which variables are not deliberately manipulated, nor is the setting controlled.  In nonexperimental research, researchers collect data without making changes or introducing treatments.
  3. 3. NEED OF NONEXPERIMENTAL DESIGN  Nonexperimental designs can be used to conduct a study are as follows:  The studies in which the independent variables cannot be maintained.  The studies in which it is unethical to manipulate the independent variable, i.e. manipulation may cause physical or psychological harm to subjects.  The studies or research situations where it is not practically possible to conduct experiments.  Descriptive-type studies that do not require any experimental approaches.
  4. 4. TYPES OF NONEXPERIMENTAL RESEARCH DESIGN Descriptive Design Univariant descriptive design Exploratory descriptive design Comparative descriptive design Correlational design Prospective design Retrospective design Developmental Research Design Cross-sectional design Longitudinal design Survey Research Design
  6. 6. INTRODUCTION…  The purpose of descriptive studies is to observe, describe, & document aspects of a situation as it naturally occurs, & sometimes to serve as a starting point for hypothesis generation or theory development.
  7. 7. MAIN FEATURES…  Descriptive designs are used to observe, document, & describe a phenomenon occurring in its natural setting without any manipulation or control.  The descriptive studies are designed to gain more information about characteristics within a particular field in the real world.  Descriptive studies provide an impression of a situation as it occurs in natural settings.  Descriptive studies do not involve the manipulation of variables, & variables are studies as they exist in the real world.
  8. 8. Count…  Descriptive design may be used to develop theories, identify problems with current practices, justify current practices, make judgments, or determine other practices in similar situations.  In descriptive studies, bias is prevented through operational definitions of variables, large sample size, random sampling techniques, valid & reliable research tools, & formal data collection methods.  Descriptive designs include identification of phenomenon of interest, identifying the variables within the phenomenon, developing operational definitions of the variables, & describing the variables.
  9. 9. TYPES OF DESCRIPTIVE DESIGN 1. Univariant descriptive design 2. Exploratory design 3. Comparative design
  10. 10. 1. Univariant descriptive design  Univariant descriptive designs are undertaken to describe the frequency of occurrence of a phenomenon.  This design does not necessarily focus on the study of a single variable; there may be one or more variables involved in the study.  For example, a researcher is interested in assessing the experiences of patients suffering from rheumatoid arthritis. In this study, the researcher may describe the frequency of different symptoms experienced by the patients & the type of treatment they received during the course of disease, etc. There are multiple variables in this research study.
  11. 11. 2. Exploratory design:  Exploratory design is used to identify, explore, & describe the existing phenomenon & its related factors.  In other words, it is not only a simple description or the frequency of occurrence of a phenomenon, but its in-depth exploration & a study of its related factors to improve further understanding about a less-understood phenomenon.  For example, an exploratory study to assess the multifactorial dimensions of falls & home safety measures for elderly people living in selected communities in the city Mehsana.
  12. 12. 3. Comparative design:  Comparative design involves comparing & contrasting two or more samples of study subjects on one or more variables, often at a single point of time.  This design is used to compare two distinct groups on the basis of selected attributed such as knowledge level, perceptions, & attitudes; physical or psychological symptoms; & so on.  For example, ‘A comparative study on health problems among rural & urban older people in district Mehsana, Gujarat.
  14. 14. INTRODUCTION…  This is a nonexperimental design, where researcher examines the relationship between two or more variables in a natural setting without manipulation or control.  In other words, it is a research design where researchers study the relationship of two or more variables without any intervention.  For example, this design was used for ‘A correlational study on the effect of smoking on lung cancer among people in Mehsana.
  15. 15. MAIN FEATURES…  In correlational studies, the researchers examine the strength of relationships between variables by determining how change in one variable is correlated with change in the other variable.  Generally, correlational studies have independent & dependent variables, but the effect of independent variable is observed on dependant variable without manipulating the independent variable.
  16. 16. Count…  In some correlational studies, identification of the independent & dependent variables is difficult; however, in most correlational studies, the independent variable is identified, which, without any intervention, influences the dependent variable. For example, this design was used in ‘a correlational investigation of the study habits & visual acuity among school children studying in selected schools in the city of Mehsana’. In this study, study habits are the independent variable, while visual acuity is the dependent variable.  In epidemiological language these studies are known as cause & effect study, where cause & effect relationship is investigate in natural settings without imposing experimental interventions. This cause & effect relationship can be investigated either in forward manner, i.e. from cause to effect (prospective) or backward manner, i.e. effect to cause (retrospective)
  17. 17. TYPES OF CORRELATIONAL RESEARCH DESIGN 1. Prospective research design 2. Retrospective research design
  18. 18. 1. Prospective research design:  A design in which the researcher relates the present to the future is a prospective research design .  Prospective studies start with a presumed cause & then go to presumed effects.  In this research design , researcher observes phenomenon from cause to effect.  Prospective designs are often longitudinal, but may also be cross sectional.
  19. 19. Count…  for example, a researcher conducting ‘a prospective correlational study on effect of maternal infection during pregnancy on foetal development & pregnancy outcome .’  In this study, the researcher starts by collecting data from pregnant women regarding any history of infection among women during their current pregnancies, next observes foetal development & pregnancy outcome, & finally analyses the relationship of maternal infection during pregnancy & foetal development & pregnancy outcome.
  20. 20. 2. Retrospective research design:  A design in which the researcher studies the current phenomenon by seeking information from past is a retrospective research design.  In this the researcher links the present phenomenon with the past events.  In other words, the researcher has a backward approach to study a phenomenon, where he or she moves from effect to identify the cause.
  21. 21. Count…  For example, this design was used in ‘a retrospective correlational study on substance- abuse-related high-risk factors among traumatic head injury patients admitted in neurosurgery ICU of Geetanjali Medical College & Hospital, Udaipur’.  In this study, the researcher first approached head injury patients, & then tried to identify the number of head injuries that occurred under the influence of substance abuse.
  23. 23. INTRODUCTION…  Developmental research design examines the phenomenon with reference to time.  Developmental research designs are generally used as adjunct research designs with other research designs such as cross-sectional-descriptive, longitudinal- correlational research designs.
  24. 24. TYPES OF DEVELOPMENTAL RESEARCH DESIGN 1. Cross-sectional design 2. Longitudinal design
  25. 25. 1. Cross-sectional design:  Cross-sectional research design is one in which researcher collects data at particular point of time (one period of data collection).  These studies are easier & more convenient to carry out.  For example, a researcher is interested in assessing the awareness on swine flu among people of an area.  Here the researcher interacts only once to collect awareness-related data from respondents.
  26. 26. 2. Longitudinal design:  Longitudinal research design is used to collect data over an extended time period (long-time study).  Its value is in its ability to demonstrate change over a period of time.  For example, a researcher in interested in the perception of nursing students towards nursing profession from the beginning of nursing programme to its end.  In this example, it is appropriate to use the longitudinal research design to study this phenomenon.  Longitudinal studies are generally classified into three types: I. Trend studies II. Panel studies III. Follow-up studies
  27. 27. Count… I. Trend studies:  These help to investigate a sample from a general population over a time with respect to some phenomenon.  Trend studies permit researchers to examine pattern & rate of changes & to make prediction about future direction based on previously identified patterns & rates of changes.
  28. 28. Count… II. Panel studies:  A panel in research is referred to the sample of people involved in a study.  In panel studies, same people are involved & over a period of time they become more informative on the phenomenon than the subjects in trends studies because the researcher can not only examine the patterns of change, & but also the reasons for change.  The same selected people are contacted for two or more times to collect further data.
  29. 29. Count… III.Follow-up studies:  These are undertaken to determine the subsequent states of subject(s) with a specific condition or those who have received a specific intervention.
  31. 31. CONCEPT…  Epidemiology is the study to investigate the distribution & causes of the diseases in population.  Therefore, epidemiological studies are generally conducted to investigate causes of different diseases in either prospective approaches (causes to effect) or retrospective designs.  Prospective studies are known as cohort studies & retrospective studies are called case-control studies.
  32. 32. Count… Cohort studies: • In this design, a longitudinal approach is used to investigate the occurrence of a disease in existing presumed causes. • For example, a researcher longitudinally observes the smokers for development of lung cancer. Case-control studies: • In this design, causes of a disease are investigated after the occurrence of a disease. • For example, a researcher investigates the history of smoking in patients diagnosed with lung cancer.
  33. 33. ADVANTAGE OF NONEXPERIMENTAL RESEARCH DESIGN  Nonexperimental research designs tend to be closest to real-life situation.  Nonexperimental research designs are most suitable for the nursing research studies..  Numerous human characteristics are inherently not subject to experimental manipulation (e.g. blood type, personality, health beliefs, medical diagnosis, etc.)  There are many variable that could technically be manipulated, but manipulated is forbidden on ethical grounds.
  34. 34. DISADVANTAGES OF NONEXPERIMENTAL RESEARCH DESIGN  The major disadvantage of nonexperimental researches is that the results obtained & the relationship between the dependent & independent variable can never be absolutely clear & error-free.  Nonexperimental studies are conducted for comparative purposes using nonrandomly selected groups, which may not be homogeneous & tend to be dissimilar in different traits or characteristics, which may affect the authenticity & generalizability of the study results.
  35. 35.