Unit 7: Data Management, Analysis and

Interpretation

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Warm Up Questions: Instructions

Take five minutes now to try the Unit 7 warm up questions in your manual.

Please do not compare answers with other participants.

Your answers will not be collected or graded.

We will review your answers at the end of the unit.

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What You Will Learn

By the end of this unit you should be able to:

describe the process for sero-survey data entry

list the variables for analysing sentinel surveillance data

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Data Entry and Management Following demographic data collection and

laboratory testing for HIV, results are brought to a site for data entry.

This site can be at the clinic, regional or national level.

If available, computers would be used to merge these results.

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Databases

Data entry is the process of entering paper records into a computer database.

Databases store the variables for each patient in the survey sample.

Data can be stored either as numbers or text. Most variables will be converted into numbers.

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Databases, Cont.

Databases and data entry screens are set up centrally by information technology staff at the national level.

Data entry screens are the forms on the computer screen into which a data entry clerk enters the data.

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Figure 7.1. Sample Data Entry Screen

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Data Dictionaries

electronic files that describe the basic organization of a project or database

contain all of the rules that guide data entry

should also be developed centrally

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Steps for Data Entry

Enter data either as numbers or text, depending on the variable, for each patient.

Save, and go on to the next patient.

Data entry should be a continuous process, to avoid backlogs and the consequent errors.

Re-enter the data. Ideally, all data are double-entered.

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Table 7.1. Checking Data for Errors

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Method Description

Automatic checking uses a computer programme with a built-in check function, such as Epi Info™

Manual checking involves looking over data to see if there are patterns that suggest problems with the data

Analysis and Interpretation Data from sentinel surveillance should be

analysed and interpreted in conjunction with other data.

These other data may include: STI prevalence behavioural data AIDS case surveillance

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Analysis and Interpretation, Cont.

Analysing and interpreting sentinel surveillance data is guided by the following questions:

Is the prevalence of HIV increasing, decreasing or remaining essentially stable?

What is the trend in HIV prevalence among 15- to 19-year-olds?

Which sentinel sites have the highest HIV prevalence?

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Analysis and Interpretation, Cont.

Which groups have the highest HIV prevalence? In which groups is HIV prevalence rising? Falling? What are the differences between sites where the

prevalence of HIV infection is low and those where it is relatively high?

What are the differences between sites where the prevalence of HIV infection is increasing, and those where there is a decrease or no change?

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Examining Trends

Analysis of HIV sentinel surveillance data should focus on the prevalence of HIV by person, place and time.

Changes in prevalence by time are most important.

Changes over time may reflect real changes in prevalence if surveillance methods are consistent.

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Examining Trends, Cont.

A focus on the trend, rather than absolute prevalence, is a principle of second-generation HIV surveillance.

Trends in HIV prevalence among 15- to 19-year-olds are most likely to reflect trends in HIV incidence.

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Analysis by Variable Sentinel surveillance data should be analysed

by each of the variables collected:

year of survey sentinel site, district, province and region age group female and male (if other than ANC) residence (for example, rural versus urban) marital status other demographic variables if collected risk behaviour if collected presence of STIs

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Analysis by Variable, Cont.

Analyse results separately for each site.

Report data for HIV-1 and HIV-2 separately, if relevant.

Results should be summarised for the entire survey sample at each site, and for each sub-group.

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Analysis by Variable, Cont.

Do not summarise sentinel surveillance data by calculating a single prevalence figure for the whole survey (that is, all the sites).

Remember, results cannot be generalised to the rest of the population.

Summary information can, at best, be presented as the median and range for each type of sentinel site, on a regional and national basis.

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Warm Up Review

Take a few minutes now to look back at your answers to the warm up questions at the beginning of the unit.

Make any changes you want to.

We will discuss the questions and answers in a few minutes.

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Answers to Warm Up Questions

1. Data Entry is the process of entering paper records into a computerized database.

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Answers to Warm Up Questions, Cont.

2. True or false? The best way to summarise sentinel surveillance data is by calculating a single prevalence figure for the whole survey. False

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Answers to Warm Up Questions, Cont.

3. True or false? Data dictionaries, that is, electronic files that describe the basic organisation of a project or database, should be developed at the local clinic level. False

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Small Group Discussion: Instructions

Get into small groups to discuss these questions.

Choose a speaker for your group who will report back to the class.

Take 15 minutes for this exercise.

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Small Group Reports

Select one member from your group to present your answers.

Discuss with the rest of the class.

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Case Study: Instructions

Try this case study individually.

We’ll discuss the answers in class.

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Case Study Review

Follow along as we go over the case study in class.

Discuss your answers with the rest of the class.

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Questions, Process Check

Do you have any questions on the information we just covered?

Are you happy with how we worked on Unit 7?

Do you want to try something different that will help the group?

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