DIFFERENT TECHNIQUES IN RESEARCHAND

SELECTION OF AN APPROPRIATE METHOD

DESCRIPTIVE STUDIES- FREQUENCY

- NATURAL HISTORY

- POSSIBLE DETERMINANTS

(HYPOTHESIS)

RELATIONSHIP BETWEEN 2 OR MORE VARIABLES

NO COMPARISON GROUP

NO ASSESSMENT OF ASSOCIATION

CROSS-SECTIONAL STUDIES

(SANP SHOT)

FREQUENCY SURVEY

PREVALENCE STUDY

RECORD OUTCOME

RECORD EXPOSURE

ARTHRITIS >>> OBESITY?

OBESITY >>> ARTHRITIS?

CASE-CONTROL STUDY

THE OUTCOME

RELATED TO

THE EXPOSUREMISUNDERSTOOD BECAUSE OF THE DIRECTION

RARE

TAKE TIME TO DEVELOP

COHORT STUDIESWHAT IS A COHORT?

TYPES OF COHORT?- CROSS-SECTIONAL

- LONGITUDINAL

- PROSPECTIVE

- RETROSPECTIVE

- COMBINED PROSPECTIVE-RETROSPECTIVE

+ EXPOSURE PRECEEDS OUTCOME

+ LESSER RECALL BIAS

+ INCIDENCE / RELATIVE RISK / ATTRIBUTABLE RISK

- LONG DURATION

- EXPENSIVE

R. C. T.

RANDOMIZATION

DELIBERATE PROCESS

IT IS WHAT WE WANTNOT ANYTHING WE GET

REMEMBER…

NO COMPARISON GROUP

NO ASSESSMENT OF ASSOCIATION

OUTCOME

EXPOSURE

OUTCOME related to

PREVALENCE OF EXPOSURE

ARTHRITIS >>> OBESITYOBESITY >>> ARTHRITIS

EVIDENCE FROM

I LEAST ONE PROPERLY DESIGNED R. C. T.

II-1 WELL-DESIGNED CONTROLLED TRIAL

WITHOUT RANDIMIZATION

II-2 WELL-DESIGNED COHORT /CASE-CONTROL

STUDY (FROM > ONE RESEARCH)

II-3 MULTIPLE TIME SERIES, WITH OR WITHOUT

INTERVENTION OR CONTROLS

III OPINIONS OF RESPECTED AUTHORIIES BASED

ON EXPERIENCE, DESCRIPTIVE STUDIES,

REPORTS, EXPERT COMMITTEES

USPSTF

• CASE STUDIES• CASE SERIES• OBSERVATIONAL STUDIES• ANALYTICAL STUDIES

ECOLOGICAL / CORRELATIONAL

CROSS-SECTIONAL / PREVALENCE

CASE-CONTROL

COHORT

• EXPERIMENTALR. C. T.

FIELD TRIALS

COMMUNITY TRIALS

OUTCOME MEASURES

• RATE = EVENTS OCCURING PER UNIT TIME

• RATIO = RELATIVE SIZE

• PROPORTION = HOW MANY OUT OF

HOW MANY

QUESTION - ANSWER

RELATIONSHIP OF ASSOCIATION IS POSSIBLE WITH:

A) DESCRIPTIVE STUDIES

B) CROSS-SECTIONAL STUDIES

C) CASE-CONTROL STUDIES

Q:

A:

RELATIONSHIP OF ASSOCIATION IS POSSIBLE WITH:

C) CASE-CONTROL STUDIES

Q:

IT IS NOT POSSIBLE TO MAKE CONCLUSIONS FROM STUDIES THAT HAVE NO COMPARISON GROUP.

TRUE

FALSE

A:

IT IS NOT POSSIBLE TO MAKE CONCLUSIONS FROM STUDIES THAT HAVE NO COMPARISON GROUP.

FALSE

Q:

Dr. GAUTAM ROY’S HYPOTHESIS:

THE EARTH IS FLAT

IS THAT A “GOOD” HYPOTHESIS?

YES

NO

A:

Dr. GAUTAM ROY’S HYPOTHESIS:

THE EARTH IS FLAT

IS THAT A “GOOD” HYPOTHESIS?

YES, IT IS!

Q:

ASSESSMENT OF ASSOCIATION IS POSSIBLE WITH:

A) DESCRIPTIVE STUDIES

B) CROSS-SECTIONAL STUDIES

C) COHORT STUDIES

A:

ASSESSMENT OF ASSOCIATION IS POSSIBLE WITH:

B) CROSS-SECTIONAL STUDIES

Q:

CHOOSING THE LAST NUMBER FROM A WAD OF CURRENCY NOTES IN A WALLET IS A RANDOMIZED PROCESS.

CORRECT

NOT CORRECT

A:

CHOOSING THE LAST NUMBER FROM A WAD OF CURRENCY NOTES IN A WALLET IS A RANDOMIZED PROCESS.

NOT CORRECT

Q:

Dr. Obgy AUSCULTATES ALL NEWBORNS IN THE LABOR ROOM AND RECORDS WHETHER V.S.D.+ OR V.S.D.–

AT THE END OF ONE WEEK HE HAS SEEN 100 NEWBORNS OF WHICH 3 HAVE VSD.

Q:

Dr. Obgy AUSCULTATES ALL NEWBORNS IN THE LABOR ROOM AND RECORDS WHETHER V.S.D.+ OR V.S.D.–

AT THE END OF ONE WEEK HE HAS SEEN 100 NEWBORNS OF WHICH 3 HAVE VSD.

IS THIS INCIDENCE?

IS THIS PREVALENCE?

A:

Dr. Obgy AUSCULTATES ALL NEWBORNS IN THE LABOR ROOM AND RECORDS V.S.D.+ OR V.S.D.–

AT THE END OF ONE WEEK HE HAS SEEN 100 NEWBORNS OF WHICH 3 HAVE VSD.

IT IS A PROPORTION

Q:IN A FACTORY, EVERY YEAR 4 MEN

AND 6 WOMEN RESIGN FROM WORK.

CALCULATE:

RATE OF RESIGNATIONS

RATIO OF MEN and WOMEN RESIGINING

PROPORTION OF MEN and WOMEN RESIGING

A:IN A FACTORY, EVERY YEAR 4 MEN

AND 6 WOMEN RESIGN FROM WORK.

CALCULATE:

RATE OF RESIGNATIONS

= 10 PER YEAR

RATIO OF MEN and WOMEN RESIGINING

= 2:3

PROPORTION OF MEN and WOMEN RESIGING

= CANNOT SAY

Q:

DISTRIBUTING EARPLUGS TO ALL

WORKERS IN A NOISY FACTORY IS AN

EXAMPLE OF:

NON-RANDIMIZED TRIAL

FIELD TRIAL

COMMUNITY TRIAL

A:

DISTRIBUTING EARPLUGS TO ALL

WORKERS IN A NOISY FACTORY IS AN

EXAMPLE OF:

COMMUNITY TRIAL