Research 36-377Dr. Wally J. Bartfay

“When the solution is simple…God is answering”

(Albert Einstein, 1879-1955)

Observational Measurement

Although most common in qualitative research, it is used to some extent in all types of studies (e.g., esp. with children)

Measurement in qualitative research is not distinct from analysis b/c tend to occur simultaneously

Observational Measurement

Not as simple as it sounds Have to 1st decide what is to be observed 2nd, need to determine how to ensure that every

variable is measured consistently in same manner

Tend to be more subjective so less credible method

Must pilot test technique & interrater reliability

Unstructured observations

Involves spontaneous observing & recording with little prior planning

Certain risk of loss of objectivity here Notes are usually taken during observation period or

shortly after “Chronologs” are detailed descriptions of subjects in

a natural environment {very intense so can’t record for more than 30 mins at a time}

Some studies, video-recordings may be made

Structured Observations

1st step is to define exactly what is to be observed 2nd step, need to determine how observations will be

recorded & coded Often a “category system” is developed for

organization & sorting behavior or events, which are mutually exclusive (e.g., infant is eating, sleeping, playing, running, climbing, sitting)

Checklists are also used to tally-up how often behaviors or events occur

Questionnaires

Are printed self-report forms designed to elicit specific information (e.g., knowledge, attitudes, intentions, opinions etc)

Subject can’t elaborate, so can be a limitation If response rate is less than 50% (esp. with mailed-

type), the representativeness is in question Can employ strategies to increase response rates

(e.g., multiple mailings, monetary incentive, prizes)

Scales

Types of self-report, more precise than questionnaires & is based on mathematical theory

Rating scales are crudest form (e.g., rate pain on scale of 1 to 10)

Likert scales are designed to determine “degree and magnitude” of opinions or attitudes on various topics (e.g., strongly disagree, disagree, neutral, agree & strongly agree)

Visual analogue scales (VAS) or magnitude scales (subject asked to place mark on vertical or horizontal line following a specific question)

The concepts of measurement in research: Nominal scales

4 levels 1st described by Stevens (1946): “NOIR” (1) Nominal-scale measurement: data organized

into categories but not ranked (e.g., gender, ethnicity, marital status, Dx)

All categories are exclusive & exhaustive Note: when data are coded for entry into a data

base, they are typically coded (e.g., 1 = male, 2 = female), but importantly, 1 is not higher or greater than 2 here)

The concepts of measurement in research: Ordinal-scales

(2) Ordinal-scale measurement: can be assigned ranked categories (e.g., levels of mobility, self-care, daily amount of exercise)

however, it CAN’t be demonstrated that intervals between categories are equal in nature (hence, unequal intervals here)

Sometimes called “ordered metric scales” All categories are exclusive & exhaustive E.g., Exercise intensity can be ranked as: 1 = mild exercise-

no SOB, no perspiration; 2 = moderate exercise, mild SOB, no perspiration, and 3 = strenuous exercise, SOB with perspiration

The concepts of measurement in research: Interval-scales

(3) Interval scales: Distances between intervals are numerically equal, & assumed to be a “continuum of values”

However, has absence of a “zero point” so not a true absolute scale (e.g., temperature, can’t say that “0” means absence of temp)

The concepts of measurement in research: Nominal scale

(4) Ratio-scales: highest form, have all criteria of previous including mutually exclusive & exhaustive categories, rank ordering, equal spacing between intervals & continuum of values + have “absolute zero” (e.g.,pulse, wt. & ht.)

Zero pulse means the absence of pulse; moreover, b/c of absolute zero, one can say that pulse of 150 is twice as fast as one of 75 beats per minute

Physiological Measures

Can be either direct or indirect, where direct are more valid

E.g., measurement of arterial pressure waveforms through an arterial catheter provides a direct measurement of blood pressure, whereas use of stethoscope & sphygmomanometer provides an indirect measure

Historical Research:

Is a systematic approach for understanding past events through the collection, organization & critical appraisal of facts

Its goal is to shed light on the past so that it can guide the present & future

Primary sources: 1st –hand eyewitness accounts (e.g., diaries, filmed interviewed)

Secondary sources: provide view of phenomenon from another’s perspective rather than 1st hand account

Multimethod Component Designs:

Here, qualitative & quantitative aspects are implemented as separate & discrete components for the overall study

These components remain separate & discrete during data collection, interpretation & reporting of outcomes

Multimethod Integrated Designs:

(1) Iterative designs: involve a dynamic in which findings from one method used to move foreword & refine alternative method (e.g., one instrument used to development & refine other instrument)

(2)Nested or embedded designs: one methodological approach is embedded in the other

(3) Holistic designs: multiply methods are integrated simultaneously rather than hierarchically

(4) Transformative designs: better suited to theory building, emphasis is on “blending” different research traditions to arrive at a better representation of the larger social context

Epidemiology

Term derived from Greek “epi” =upon & demos = people; logos = science

Study of “epidemics” Investigate how various states of health are

distributed in populations & what environmental conditions, life-styles or other circumstances are associated with presence or absence of diseases

Patterns of symptoms often “cluster” in a particular age group, geographical area or time period (1st clue in learning what the “cause” is)

Epidemiology: historical roots

Since antiquity, people have attempted to explain what “causes” disease/ illness

Often attributed to supernatural events Hippocrates (460-377 BC) attempted to explain

disease on a rationale basis In several books (“Airs, Waters & Places, Epidemics

I & II”),he pointed-out that disease is a mass phenomena & noted that environment & lifestyle are related to occurrence of disease

Natural History of Disease

Is a process by which diseases occur & progress in the human host, involves 3 factors:

(1) Agent: is a factor whose presence causes a disease or one whose absence causes disease (chemical, biological)

(2) Environment: refers to all external & internal conditions & influences affecting the live of living things (physical, socioeconomic, biological environment)

(3) Host: human in whom an agent produces disease

Causal relationships:

Direct causal association: those in which a factor causes a disease with no other factor intervening

Causal factor Outcome E.g., Tubercule bacillus Tuberculosis

Causal relationships:

Indirect causal associations: 3rd intervening variable, occupies an intermediate stage between the cause & effect

A B C D E.g., Cigarette smoke (A) damages

respiratory epithelium (B); this then increases susceptibility of epithelium to infection (C); & this results in chronic bronchitis

The Disease Process

Occurrence of disease in human host is not a single event at one point in time, but a process

“Clinical horizon”: imaginary line dividing the point where there are detectable signs & symptoms form that were there are not

Disease process natural Hx. Is divided into 2 board periods: (i) Prepathogenesis & (ii) Pathogenesis

Prepathogenesis Period:

(1) Susceptibility: (a) interrelations of various host, agent, &

environmental factors bring host & agent(s) together (b) Disease-provoking stimulus is produced in the

known host (remains asymtomatic) (2) Adaptation: processes are initiated Research emphasis here is “primary prevention”

(e.g., health promotion/ education, immunizations, sanitation, removing occupational hazards, dietary nutrients etc)

Pathogenesis Period:

(1) Presymptomatic disease/ Early pathogenesis stage

(a) Interaction of host & stimulus continue after failure of adaptive response (e.g., immune system is ineffective)

(b) Stimulus or agent becomes established (e.g., if infectious agent, increases by multiplication)

(c) Start of tissue & physiological changes

Pathogenesis Period:

(2) Discernible early lesions stage: (a) Clinical recognition of disease is possible via lab

or other Dx. Tests to detect early physiological changes

(b) Pt. develops early symptoms that go unrecogized as problematic

Research emphasis here is “secondary prevention” (e.g., early Dx. & screening, prompt Rx., case finding)

Pathogenesis Period:

(3) Clinical Disease stage: (a) Acute illness (b) Disability (c) Defect (d) Chronic state (e) Death Research emphasis here is on Rx. to arrest disease

process (e.g., meds, surgery) & “tertiary prevention” (e.g., rehab. retraining r/t ADL post stroke)

“That’s all folks!”