survey-steps in planning helath programme
- 1. Introduction Definitions Uses Types Methods o f data c o l l e c t i o n Scientific Steps Basic O r a l H e a l t h Survey PathFinder Survey WHO O r a l h e a l t h assessment form Objective: To understand what is a survey and methods involved in it.
- 2. Definition: A survey is an investigation in which information is collected systematically, but in which experimental method is not used. Surveys are methods for collection of data, analyzing and evaluating them in order to determine the amount disease problems in a community and also to identify cases that have not been identified.
- 3. A survey is an investigation about the characteristics of a given population by means of collecting data from a sample of that population and estimating their characteristics through the systematic use of statistical methodology. Glossary of Statistical Terms: Dec 20, 2005 Definition:
- 4. USES OF SURVEY: 1. Monitoring trends in oral health and disease. 2. Policy developmen t 3. Program evaluation 4. Assessment of dental needs 5. Providing visibility for dental issues - - by repeating national surveys periodically. WHO’s pathfinder survey - assess trends - are valid enough to support national policy decisions. - - Scotland - successfully used survey data to establish oral health strategies. American states: focus shift F mouth rinsing to Sealant programs after statewide surveys showed high carious lesions in pits and fissures.
- 5. A D VA N TA G E S : Provides info. on oral health status Rates and indices can be calculated. Association and correlation between variables can be identified. Reasons for utilization/non utilization of oral health services. Reliable, complete and accurate
- 8. SCIENTIFIC METHOD IN CONDUCTING A SURVEY 1. Establishing the objective 2. Designingthe investigation 3. Selecting a sample 4. Conducting the examination 5. Analysis of data
- 9. 1. ESTABLISHING THE OBJECTIVE Investigator must be absolutely clear about the objective of the investigation before considering its design. - Hypothesis to be tested - describing what is to be measured. NULL HYPOTHESIS
- 10. 1. ESTABLISHING THE OBJECTIVE e.g.: There is NO difference in periodontal status of males and females aged 35-44 years in Central India. e.g.: To determine the prevalence of dental caries among 12 year old school children in Central India.
- 11. 2. DESIGNING THE INVESTIGATION It is important to prepare a written protocol for the survey : • Main objective and purpose of the survey • Description of the type of information to be collected and methods to be used. • Sampling methods to be used. • Personnel and physical arrangement. • Statistical methods to be employed. • A provisional budget.
- 12. 2. DESIGNING THE INVESTIGATION Case Control Cohort CONTROLS: A parallel be studied group in the exposed same way. must also to avoid argument - - imply cause & effect relationship Prevalence DESCRIPTIVE Incidence SURVEY ANALYTICAL
- 13. 3. SELECTING THE SAMPLE The process of choosing some representative members from the target population. “reference” or “parent” population
- 14. 3. SELECTING THE SAMPLE
- 15. 3. SELECTING THE SAMPLE SIMPLE RANDOM SAMPLING Populat i on Sampl e - every item in the population has an equal chance of being included. - when population is small, homogeneous and readily available. - does not ensure randomness.
- 16. 3. SELECTING THE SAMPLE SIMPLE RANDOM SAMPLING Lottery Method Table o f random numbers - - various units of population are numbered on small and identical slips or papers, folded and mixed thoroughly. A blindfold selection is then made to constitute the desired sample size. - - select at random any page, & pick up any row & column at random. Random tables: Tippets (1927) Fisher and Yates (1938) Rand Corporation (1953)
- 17. 3. SELECTING THE SAMPLE STRATIFIED RANDOM SAMPLING - - - when population is composed of diverse segments. population under study is 1st divided into homogeneous groups ‘strata’ Sample is drawn from each stratum using simple random method.
- 18. 3. SELECTING THE SAMPLE - - - - Examples: Workers: skilled, unskilled, clerical, non clerical groups. Sociological (religion): Hindus, Muslims, Christians, Sikhs, Buddhists, Jains etc. Age-group wise etc.
- 19. 3. SELECTING THE SAMPLE SYSTEMATIC RANDOM SAMPLING - - when a complete list of population from which sample has to be drawn is available. Here we take every ‘K’ th house or item from the sampling frame.
- 20. 3. SELECTING THE SAMPLE MULTISTAGE SAMPLING - - Random selection is made of of primary, intermediate and final units from a given population. The area under investigation is scientifically restricted to a small number of ultimate units, that are representative of the whole. - e.g.: Nutritional status of India
- 21. 3. SELECTING THE SAMPLE MULTIPHASE SAMPLING - Part of info. is collected from the whole sample, and part is from the sub-sample. - eg: Tuberculosis Survey. 1. Mantoux test (simple and cheap) - done to all cases. 2. Chest X ray (for positive cases) 3. Sputum examination (concentrate technique)
- 22. 3. SELECTING THE SAMPLE - - - - - CLUSTER SAMPLING ‘Cluster’: smallest units in which the population can be described. e.g.: villages, wards, slums of towns, factories, school children etc. Used in National surveys. Clusters are internally heterogeneous, whereas strata are homogeneous. Usually 30 clusters - randomly selected - entire population in cluster is studied.
- 23. 3. SELECTING THE SAMPLE QUOTA SAMPLING - - - Stratified random sampling minus randomization. the researcher decides in advance on some key characteristics that will define the strata. The respondents may be selected just because they are accessible to the examiner.
- 24. 3. SELECTING THE SAMPLE CONVENIENCE SAMPLING - - when selection is made from available resources, like telephone directory, automobile registers etc. an acceptable approach while using a qualitative design.
- 25. 3. SELECTING THE SAMPLE VOLUNTEER SAMPLING
- 26. 3. SELECTING THE SAMPLE SNOWBALL SAMPLING - Researcher selects a few participants, who then suggest others who may be willing to participate.
- 27. 4. CONDUCTING THE EXAMINATION A n o r d e r l y s c h e d u l e - f o r d a t a c o l l e c ti o n . in c lu d e a l l the re s o u rc e s re q u i re d to c a r r y o u t s u r ve y L o c a l , r eg io n a l o r n a ti o n a l a u t h o r i t y
- 28. 4. CONDUCTING THE EXAMINATION L en g th o f ti m e to ex a m i n e a subj ec t d e p e n d s o n ex t e n d o f d e t a i l a n d i n c l i n a ti o n o f the examiner. B a s i c o r a l health e x a m i n a ti o n : • 5 - 10 m i n u tes • 15 - 20 m in u tes
- 29. 4. CONDUCTING THE EXAMINATION • • 3 0 m o u th m i r r o r s 3 0 per io d o n ta l probes pa i r s o f tweez er s c o n c . s t e r i l i z i n g s o l u ti o n wash basin c l o th/ pap er ha n d towels g a u z e • • • • •
- 30. 4. CONDUCTING THE EXAMINATION • C u r r en t n ati o n a l r ec o m m en d ati o n s a n d s t a n d a r d s s h o u l d be f o l l o w e d f o r I n f e c ti o n c o n t r o l Waste d i s p o s a l Di spo s a bl e m a s k s, g l o v es, pr o tec ti v e eyewea r r e c o m m e n d e d . • • •
- 31. 4. CONDUCTING THE EXAMINATION EXAMINATION AREA C H A I R : preferable with a h e a d rest. Mo st c o m f o r ta bl e s itu ati o n i s f o r the subj ec t to be o n a table/bench, a n d e xa m i n e r to sit be hi nd the subject’s head. I L LU M I N AT I O N : a separate u n i t la m p atta c he d to hea d o f the ex a m i n er fibre o p ti c l i g h t s o u r c e
- 32. 4. CONDUCTING THE EXAMINATION EXAMINATION AREA C L E A NI NG : so m e m etho d to r em o v e l o o se de br is where necessary. ASSESSMENT FORMS: adequate supply. Av o i d a n c e o f c r o wd i n g a n d n o i se a r o u n d the examiner. R E C ORDE R : l i v e o r ta pe f o r r ec e iv in g i n f o r m a ti o n c a l l e d by the examiner. O R G A N I Z I N G C L E R K : to m a i n t a i n c o n s t a n t fl o w f subjects a n d to enter g e n e r a l d e s c r i pti ve i nfo .
- 33. 4. CONDUCTING THE EXAMINATION T Y P E 1: C o m p l e t e e x a m i n a ti o n u s i n g m o u t h m i r r o r & explorer, g o o d i l l u m i n a ti o n , f u l l m o u t h ra d i o g ra p h s , & a d d i ti o n a l d i a g n o sti c m etho d s (pu l p testi n g , stu d y m o d e l s , t r a n s i l l u m i n a ti o n etc.) T Y P E 2: L i m i t e d exa m i n ati o n , u s i n g m i r r o r a n d ex pl o r er, bi tewi n g r a d i o g r a phs. PA r a d i o g r a phs if i n d i c a t e d . T Y P E 3 : I n spec ti o n u sin g m o uth m i r r o r & ex pl o r er, g o o d i l l u m i n a ti o n . T Y P E 4 : Scr een in g pr o c e d u r e - to n g u e d epr esso r, ava i l a b l e i l l u m i n a ti o n .
- 34. 4. CONDUCTING THE EXAMINATION For an epidemiological study of dental conditions: Examination method Diagnostic aid Data recording Training and calibration Consent
- 35. 4. CONDUCTING THE EXAMINATION Examination method WHO - manual ‘Oral Health Surveys- basic method’ to standardize survey methods. For comparison of findings at national and international levels.
- 36. 4. CONDUCTING THE EXAMINATION Diagnostic aid Basic requirement : a chair, a source of illumination and some means to clean debris off teeth. Diagnostic criteria Classification for diagnosis must be well defined. Diagnostic method should be Valid (ability to measure what it is intended to measure) Reliable (ability to give same results if
- 37. 4. CONDUCTING THE EXAMINATION Data recording Recording method should be decided in advance. • Record sheet • tape recorder/camera
- 38. 4. CONDUCTING THE EXAMINATION Training and Calibration Each examiner should diagnose the condition in the same way on every occasion. Intra-examiner variability: ‘reproducibility test’ Helps the examiner to check their ability to produce same diagnosis of same condition at different occasions. Inter-examiner variability: if more than one examiner. undergo ‘training and calibration exercises’
- 39. 5. ANALYZING DATA Oncethe examination is complete, the work of assembling the material and interpreting it begins. ANALYSIS: “computation of certain measures along with searching for specific pattern of relationships that exist among data groups”. 2 components • Data processing (statistical analysis)
- 40. 5. ANALYZING DATA Depending on measurement and sampling procedures, the analysis of collected data can be • • Statistical (inferential) Non-statistical (descriptive) TYPE OF MEASUREMEtfT TYPE OF TEST tfominal tfonparametric tests Ordinal Interval Parametric tests Ratio
- 41. 5. ANALYZING DATA • • Homogeneity of variance Variables - true numerical “distribution free tests”
- 42. 5. ANALYZING DATA Depending on number of variables: • one variable - unidimensional analysis • t wo variables - bivariate analysis • more than t wo - multivariate analysis Depending on type of analysis to be done - - Requires estimating a parameter • Point estimate (measures of Central tendency) • Interval estimate (measures of dispersion) Testing of hypothesis Z test, t test, chi square test, ANOV A.
- 43. 6. Drawing the conclusion Conclusions should be specifically related to the investigation that has been carried out. Construction of a report with or without a set of recommendations. Clearness and simplicity should be sought.
- 44. 7. PUBLISHING THE RESULTS INTRODUCTIO N • • • • Reasons for conducting the survey Review of literature Objectives of investigation Hypothesis to be tested MATERIALS AND METHODS • Selection & description of sample • Methods used for diagnosis • Diagnostic criteria •Technique of investigation RESULTS •Appropriate tabulation & illustration
- 45. LIMITATIONS OF SURVEY APPROACH 1. Surveys are dependent on the chosen sampling frame. The representativeness of a survey is entirely dependent upon the accuracy of the sampling frame used. Sometimes it is not possible to identify an accurate or up-to-date sampling frame. 2. Interview surveys are only as good as the interviewers asking the questions. The outcome of a survey may be influenced by interviewer error and bias. It is important that all interviewers receive proper training for each project. 3. Surveys are not so good at explaining why people think or act as they do.