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Learn the purposes, principles, and techniques of presenting health data through tables, graphs, and numerical measures. Develop skills in proper information presentation.
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Health Management Information Systems Presenting informationcommunicating meaning João Carlos de Timóteo Mavimbe Oslo, April 2007
Presenting information • LEARNING OUTCOMES: • By the end of the session you should be able to: • Understand the purposes and basic principles of data presentation • Present data in simple tables • Select appropriate graph types to present the various types of data • Build appropriate graphs for display of data • Develop skills in proper presentation of information
The information cycle: Presenting Information Tables, Graphs, Population, Maps Presenting Interpreting ANALYSIS Processing USE Collection Input Raw data
Preparing for Presentationessential ingredients: 3 C + 1 T Timely • Correct • good quality data • Complete • submission by all (most) reporting facilities • Consistent • data within normal ranges • reflects community shifts • clear definitions
Presenting information • What information is presented? • Why is information presented? • How is information presented?
What “information” is presented? • Analysed data (mainly) • Collated data (sometimes) • Raw data (rarely)
Why is information presented? To promote understanding and facilitate interpretation: • Appropriate interpretations • what linkages are possible? (correct, logical, sensible) • may answer important questions • may result in action • Possible interpretations • are context dependent (population, health, service status) • depend on data quality • should depart from data definitions
Why is information presented? To share knowledge with whom? To provide feedback to whom?
How is information presented? Three ways of presenting data: • Tabular:frequency distribution table • Graphs:Histogram, Line diagrams, Scatter plot, Bar chart, Pie chart • Numerical: Measures of Typicality or Center: mode, median, mean Measures of Variability (or Spread): range, variance, SD Measures of Shape: skewness, kurtosis Proportions, rates, ratios
Types of data They determine the most appropriate tool for presenting data.
Data Quantitative (Numbers) Qualitative(Characteristics) Discrete Continuous Discrete categories/ kinds measures counts
Numerical Data • Continuous – they are measurable • Examples: • Age of patients in years or months • Weight of newborn in grams • Discrete – they are counted (possible values are distinct or separate): • Examples: • The size of a family expressed as the number of children • The number of days since the begining of a disease units of measurement
Non-numerical Data • They are the qualitative description of categories of a characteristic. Examples: • The gender of a patient is recorded as “male” or “female”; • The list of diagnoses in a health center;
Data Quantitative Qualitative Discrete Continuous Discrete Number of beds per HC Bed ocupation Addresses of patients Number of children Patient temperature in ºC Cost of a drug presciption Population of a village Age of patients in years Number of broken vials Health area Exercise:Mark with in the blank spaces
BEDS – an example of how a single data element may provide different types of data. • Number of beds • Type of bed • Height of the bed(from mattress to floor)
Tables: saying it with figures Table No. Source: Comments: Date:___/___/___
Tables • Beware information overload: • easy to produce – difficult to use • Ideally should contain: • Few rows • One category • Uses: • assess quality • trends over time • make comparisons • pick up outliers, gaps
Tables Table 1: Number of children per family in Maputo, 2005 Source: Statistics & Planning Directorate, 2005
GRAPHS: talking with pictures(…a visual representation of data) • Advantages: • Information is instantly conveyed • Data are presented clearly and simply • Can expose relationships and patterns • Detect trends over time • Can be used to emphasise information
Graph Elements Title – descriptive clinic name, what is graphed and the time period Y axis – must ALWAYS be labeled Y axis label X axis – label if appropriate Key or legend – used if more than one element graphed Y X Source: Notes: Scale – be appropriate
Golden rules for graphs • Never put too much information in the graph. KEEP IT SIMPLE. • Never mix different activities: stick to one group of people or diseases or services. • Label your graph: always have a clear heading, easily read labels on the axes, and a legend which explains each of the lines or bars. • Select scales that fit the entire graph on both axes. • Where possible, draw a target line or reference point to show where you are aiming at.
Data Quantitative (Numbers) Qualitative(Characteristics) Discrete Continuous Discrete categories/ kinds measures counts Types of graphs • They follow the types of data available:
Type of graphs • Continuous data • histograms • line Graphs • scatter Graphs • Discrete Data • bar graphs • pie charts
Graphs for sets of continuous data • histograms • line graphs • cumulative line graphs
Line graph Graph 2: PHC headcount under 5 years old, Manyara Clinic, 2001 • accurate, can show minute changes in the relationships between 2 major variables • displays trends over time • can be useful if more than one data item is used
Bar graph versus Line graph which one is best?
Line graph, with 2 dependent variables The larger the font, less detail will be shown in the axes Remember to remove the silly gray background to improve contrast!
Line graph, for cumulative coverage • Simple and effective monitoring tool • Used when targets are set for a year i.e. immunization, antenatal coverage, etc. • Each month, data is graphed individually and also added to the previous month • A target is set, a target line is drawn and progress is monitored with respect to the target line
Graphs for sets of discretedata • pie charts • bar graphs
Bar graph, simple • displays data over time or can compare 2 or more different facilities / districts / regions / years
Bar graph, stacked • has the advantages of a circle graph: it displays the quantities, but it also shows the relative proportions of the categories to each other and to the whole.
Pie chart or circle graph • best type of graph for showing the relative proportions of different categories to each other and to the whole • can be used when exact quantities are less important than the relative sizes of the parts
Common faults with graphs • No title • No labels for the variables • No units of measurement (or incorrect units!) • No scale markings (or just too many!) • Inappropriate scale choice – data points should be evenly represented • Incorrect choice of independent (x-axis) and dependent (y-axis) variables • No legends when needed
Graphs- population pyramids • they may highlight the differences in age distribution between males and females as well as proportional age categories