Source of Data/Ethical Concerns

(1)

Source of

data/ethical

concerns

Wei-Chu Chie

(2)

Steps of a research

• Conceiving the research question

• Choosing the study subjects

• Planning the measurement

• Conducting the study

• Analyzing the data

• Writing the report

(3)

A good research question

• Feasible

• Interesting

• Novel

• Ethical

• Relevant

(4)

Data: subjects and

measurement

– Subjects

• target population (research question) • accessible population (study plan)

• intended sample (study plan) • actual subjects (actual study)

– Measurement

• phenomena of interest (research question) • intended variables (study plan)

(5)

Research validity

– Internal validity

• how well the findings of the study infer to the truth of the study (study plan)

– actual subjects to intended sample

– actual measurement to intended variables

– External validity

• how well the truth in the study infer to the truth in the universe (research question)

– intended sample to accessible and to target population

(6)

Source of data

• Primary

– collect original data by the researcher

him or herself

• Secondary

– use existing data

• Tertiary

(7)

Primary data: subjects

– Specification: target to accessible population

• target population: well suited to the research quest ion

• accessible population: representative of the target population and easy to study

– Sampling: accessible population to sample

• intended sample: representative of the accessible po pulation and easy to study

– Question of external validity (generalizabilit y)

• usually less strict in epidemiologic and clinical ou tcome research

(8)

Primary data: subjects

• Inclusion criteria: be specific

– specifying the characteristics that define

population relevant to the research

question and easy to study

• target population: demographic and clinical characteristics

• accessible population: geographic and temporal characteristics

(9)

Primary data: subjects

• Exclusion criteria: be parsimonious

– highly likely of being lost to follow-up

– inability to provide good data

– ethical barriers

– refusal

(10)

Primary data: subjects

• Sampling

– probability sampling: *often used in PH

studies

• simple random • systematic

• proportion to population size (PPS) • stratified random

(11)

Primary data: subjects

• Sampling

– non-probability sampling

• consecutive *most often used in clinical studies

• convenience • judgmental

• Actual subjects

– non-response ‘bias’ and its prevention

– systematic error/internal validity

(12)

Primary data: measurement

• Measurement scale

– categorical (nominal) including binary

– ordinal or rank

– interval or continuous

(13)

Primary data: measurement

• Precision

– free of random error

• Accuracy

– free of systematic error

• Validity of the instrument vs. internal

validity of the study

(14)

Primary data: measurement

• Precision: free of random error

– the degree to which a variable has

nearly the same value when measured

several times

– coefficient of variation (C.V.)

– reliability

(15)

Primary data: measurement

• Accuracy: free of systematic error

– the degree to which a variable actually

represent what it is supposed to

represent

– validity

– with gold standard

• sensitivity

• specificity

(16)

Primary data: measurement

• Accuracy: free of systematic error

– without gold standard

• face validity & content validity • criterion-related validity

– convergence validity – divergence validity

(17)

Primary data: measurement

• Choice of proper instrument

– Status or time to event:

• binary/nominal

• registry/clinical or other records • classified from interval scale

– Surrogate endpoint:

• nominal/ordinal/interval

(18)

Primary data: measurement

• Choice of proper instrument

– quality of life

– functional status

– satisfaction

– cost

• interval scale • questionnaires

(19)

Primary data: measurement

• General rules of increasing precision

– standardization of methods

– training and certifying observers

– refining the instrument

– automating the instrument

– repeating the measurements

(20)

Primary data: measurement

• General rules of increasing accuracy

– the same as that for precision except

repeated measurements

– making un-obstructive measurements

– blinding

(21)

Primary data: measurement

• Questionnaire

– use existing vs. self-designed ones

– copyright and translation right

– standardized translation procedure

• forward

• backward

(22)

Primary data: measurement

• Questionnaire design

– questions: open vs. closed-ended

– format/wording

• clarity

• simplicity • neutrality • specific

(23)

Primary data: measurement

• Questionnaire design

– Scale

• summative (Likert) • cumulative (Guttman)

– Draft and content or face validity exami

nation

– Coding/precoding

– Pretest and revision, reliability and va

lidity

(24)

Primary data: measurement

• Questionnaire use

– Administration

• interview: face-to-face, group interview, telephone

• self-administered: concurrent, mailed, internet

– Quality control

(25)

Primary data: ethical

concerns

• Subjects

– four principles of medical ethics:

• autonomy

• beneficience

• non-maleficence • justice

– informed consent/not limited to experime

ntal studies/

IRB: institutional review board

(26)

Primary data: ethical

concerns

• Subjects source

– institutions/physicians

• Cooperation/collaboration

– right and duty

– authorship

• Instruments

(27)

Secondary data: overview

• Strengths

– speed: especially easy in the e-era

– economy

• Weakness

– quality unsure

(28)

Secondary data: types

– Aggregate: group as unit

• vital statistics

• disease incidence/prevalence of geographic area • economic, demographic, … data/census

– ecological correlation study/ecological fallacy

– Individual: individual as unit

• government statistics: mortality, cancer registry, ... • hospital discharge data/health insurance data, ... • previous studies of different purposes

(29)

Secondary data: how to

start

– Find data bases to fit a research question

• choose a research question/literature review • list predictors/outcome variables

• identify proper data bases that might include the variables

• be familiar with the data bases/consultation • choose the best one/application

• formulate hypotheses and statistical methods • data analysis

(30)

Secondary data: how to

start

– Find research questions to fit existing

data sets:

• the reverse way of usual research design • choose (a) data base(s)/application

• be familiar with the data bases/make a flow sheet of variables/identify pairs/groups of variables of interest

• literature review/experts consultation

(31)

Secondary data: data

linkage

• Making use of more than one data

bases

• Key linkage variable:

– a variable that all the data bases possess – e.g. individual citizen’s ID

– easy in electronic data bases

• Enrich the ‘utility’ of data

– e.g. hospital discharge data --- mortality registry-- survival of a certain disease

(32)

Secondary data:

Public accessible

secondary data bases in Taiwan

– aggregate data: national and local

• 內政部台閩地區人口統計 • 衛生署衛生統計

• 其他政府出版品集體統計資料

– individual data:

• mortality (death certificate) registry 死亡檔 (original ID)

(33)

Secondary data:

Public accessible

secondary data bases in Taiwan

– individual data: previous studies

• 中研院調查研究工作室學術研究資料庫

– 台灣地區社會變遷基本調查 – 政大選舉中心選舉調查

– 國民營養狀況變遷調查等

• Individual-based government surveys

– 生育力調查 – 收支調查

(34)

Secondary data: p

ublic inaccessible

secondary data bases in Taiwan

• NHI original data (ID not scrambled)

• Household registry data

• Health station-household data: PHIS

• Military service data

(35)

Secondary data: hospital-based

data ready for clinical research

• Data kept by separate hospitals

– computerized

• hospital cancer registry • hospital NHI claims data

• other computerized records

– not computerized

• written form on medical records • special tests/examinations/studies

(36)

Secondary data: other

countries

– US

• government-owned

• separate health insurance, managed care, HMOs

– Scandinavian countries

• large and detailed medical and national files with original ID, ready to link

(37)

Secondary data: ethical concerns

and related limitations

– Protection of privacy/confidentiality

• personal electronic data protection law • scrambled ID: NHI data base

– inaccessible to original record/individual, unable to examine validity of data or improve quality – data bases linkage impossible: poverty of

contents

• third party linkage/removal of ID before use: cancer registry

• researcher/investigator agreement: hospitals • informed consent: certain studies/hospitals