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 doubleentered.
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Table 7.1. Checking Data for Errors
Method
Automatic
Manual
Description
checking uses a computer programme with
a built-in check function, such as Epi Info™
checking involves looking over data to see
if there are patterns that suggest problems
with the data
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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 secondgeneration HIV surveillance.

Trends in HIV prevalence among 15- to 19year-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 subgroup.
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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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