Presentation on theme: "Formulation of the objectives Variable vs. Concepts Types of measurement scales Dr. Sa’ed H. Zyoud."— Presentation transcript:
Formulation of the objectives Variable vs. Concepts Types of measurement scales Dr. Sa’ed H. Zyoud
Formulation of the objectives They are the goals you set out to achieve in your study. You should word them clearly and specifically (so as to be clear to the reader). Two types – General (main objective). The main association/relationship you want to discover or establish. –Specific (sub-objectives).
Formulation of the objectives –Specific (sub-objectives). Specific aspects of the topic that you want to investigate within the main framework of your study. Numerically listed. Wording should clearly, completely and specifically Each objective should contain only one aspect of the Study.
Formulation of the objectives The objectives should start with words such as: ‘to determine’ ‘to find out’ ‘to ascertain’ ‘to measure’ ‘to explore’
Formulation of the objectives The wording of objectives determines the type of research - Descriptive, Correlational, Experimental The wording of objectives determines the type of research design you need to adopt to achieve them - Observational study, Experimental study
Formulation of the objectives Descriptive studies: -To describe the care provided to diabetic patients. -To find out the opinion of the patients about the medical facilities provided to them. - To describe the demographic and clinical characteristics, risk factors and comorbidities of patients admitted with ischemic heart disease. - To describe the medications given to diabetic patients at discharge.
Formulation of the objectives Correlatinal studies: -To ascertain the impact of anticoagulant use on the risk of thromboemobolism. -To compare the effectiveness of warfarin and heparin on the risk of thromboemobolism. - To assess the potential benefits of previous aspirin use on reducing mortality after ischemic heart disease. - To determine the variables upon admission that are considered the most predictive of in-hospital mortality among ischemic heart disease.
Formulation of the objectives -To ascertain if an increase in working hours will increase the incidence of drug/alcohol abuse. - To determine if the previous aspirin use can reduce mortality after ischemic heart disease.
Formulation of the objectives –Characteristics of the objectives Clear Complete Specific Identify main variables to be correlated Identify the direction of the relationship
Formulation of the objectives - Identify main variables to be correlated The concepts used should be set in measurable terms so that the extent of variations in respondents’ understanding is reduced if not eliminated. Techniques about how to operationalise concepts, and knowledge about variables, play an important role in reducing this variability.
Formulation of the objectives - Identify main variables to be correlated When people express their feelings or preferences, they do so on the basis of certain criteria in their minds. Their judgment is based upon indicators that lead them to conclude and express that opinion.
Definition of the Variable
Variable vs. Concepts - Variable: Can be measured via a specific scale. - Concepts mental images or perceptions, and their meaning vary from individual to individual (subjective impression) and can be converted into variables by indicators. indicators- a set of criteria reflective of the concept which can then be converted into variables..
Variable vs. Concepts - Variable: - Gender. - Age - Weight - Religion - Income - Concepts -Excellence - Rich -Satisfaction - Compliance - Violence
Concepts … Indicator … Variable The choice of indicators for a concept might vary with researchers, but those selected must have a logical link with the concept.
Concepts … Indicator … Variable ConceptIndicatorVariablesWorking definition RichIncome Asset IncomeIf more than …. KnowledgeSet of questionsTotal scoreIf more than …
Types of measurement scales Three categories: –Nominal (classificatory) scale –Ordinal or ranking scale –Numerical scale
Types of measurement scales Nominal (classificatory) scale: dichotomous or binary A nominal scale enables the classification of individuals, objects or responses into subgroups based on a common/shared property or characteristic. A variable measured on a nominal scale may have two or more subcategories depending upon the extent of variation. The variable “gender” can be classified into two sub- categories: male and female. ‘Types of stroke’ can be classified into 3 sub-categories, outcomes (alive or dead), yes or no. Nominal data are describe as percentage or proportion.
Types of measurement scales The ordinal or ranking scale: Besides categorizing individuals, objects, responses or a property into subgroups on the basis of common characteristic, it ranks the subgroups in a certain order. For example, ‘income’ can be measured either quantitatively (in dollar) or qualitatively using subcategories ‘above average’, ‘average’ and ‘below average’. The ‘distance’ between these subcategories either equal or not equal. ‘Socioeconomic status’, ‘attitude’, ‘functional outcome’ and ‘knowledge’ are variables that can be measured on ordinal scale. Coma scale, disability scale Likert scales
e.g. GLASGOW COMA SCALE Severe, with GCS < 9 Moderate, GCS 9–12 Minor, GCS ≥ 13.
Types of measurement scales Numerical scale : -Continuous scale: has values on a continuum (e.g. age:15, 17.5 -Discrete scale: has values equal to integers( number of fractures, number of visits)