Presentation on theme: "1 Table design Module 3 Session 2. 2 Objectives of this session By the end of this session, you will be able to: appreciate the different type of objectives."— Presentation transcript:
2 Objectives of this session By the end of this session, you will be able to: appreciate the different type of objectives that may arise in real life surveys identify appropriate tables for a given set of objectives and research questions use this knowledge to ensure relevant questions are incorporated into corresponding survey questionnaire
3 Survey Objectives Surveys conducted by Statistics Offices are done to provide information on which policy decisions can be made. The stated objectives can often vague, e.g. the objective of this survey is to collect information about……. Objectives must be clear so that correct information can be collected, presented and interpreted.
4 Survey Objectives Study purpose must be clear… … so that questionnaire can contain correct questions for addressing objectives … and so that correct summary tables can be produced that address the objectives. At the planning stage it should be possible to identify the essential tables that will address the objectives of the survey.
5 Objectives related to estimation e.g. To estimate median income of dwellings in slum areas of a city proportion of rural households that have no access to a medical facility within 3 kms maternal mortality rate, i.e. deaths per 1000 live births of mothers from puerperal causes mean yield per hectare of pigeonpea production in small-holder commercial farms
6 Objectives related to comparisons Questions of interest may be: does a newly introduced farming practice for managing banana plants result in higher yields compared to a standard practice? is there a difference in access to health facilities between rural & urban areas? is there evidence that children from poorer families have less opportunities for entering higher educational institutions?
7 Objectives related to relationships Is there a relationship between: consumption expenditure (as a proxy for income) and household demographics and assets? childrens enrolment in primary school and educational level of household head? mean number of visits by household members to a health clinic and their level of access to clean water and adequate sanitary facilities?
8 Tables to address objectives Need to consider: Which questions (variables) provide the data Unit on which measurement is being made e.g. household, household member. Whether there is a need to calculate any new variable(s) Type of data e.g. continuous, categorical Type of summary statistic e.g. mean, percentage
9 Example 1(a) - simple example Objective: Objective: What proportion of rural households have no access to a medical facility within 3 kms of their homestead Unit: Household Question on questionnaire (variable): What is the distance to the closest medical facility (in km) Type of summary statistic required: Percentage (of households)
10 Example 1(a) …cont. Distance to closest medical facility is a continuous variable. To produce an appropriate table for this particular objective need to calculate a new variable: Derived variable: Code as 1 if above measurement > 3 kms, 0 otherwise Other variable(s): Rural/urban status of hhold Need this to select out cases that are rural.
11 Table… (basics!) Have access… 1. Number of households 2. Percentage of total 50 20% Dont have access… 1. Number of households 2. Percentage of total 198 80% OverallTotal number of households in Rural area 248 … for example
12 Example 1(b) Objective: Objective: Are rural and urban communities similar with respect to their access to a medical facility. What type of summary now? Two approaches: 1) Summarise distribution of distances to facility using means etc. 2) Summarise distances using percentages for different ranges of distance.
13 Table…(basics!) Distance to nearest medical facility (km) RuralUrban No. of households mean sd minimum maximum
15 Example 1 Which table to use? - depends on objectives. Have they been stated clearly enough? Are policy makers interested in average distance? Or do they want to know what proportion of households are within certain distances ?
16 Example 2 (hierarchical) Objective: Objective: From the UNHS2 survey, is there is a relationship between proportion of people who are sick in a household within the last 30 days and their access to good drinking water. Units: both household (access to water) and household member (sick in last 30 days) Questions (variables): Did individual fall sick in the last 30 days? But what about access to good drinking water? What variables represent this?
17 Activity In small groups, produce a table to address this objective. Some considerations are: Identify a variable, or variables, to for access to good drinking water. Do you need to derive any new variables. And if so what are they? What statistical summaries do you want to include in your table.