Graphs are now almost exclusively computer generated and epidemiologists become more and more dependent on the possibilities and limits of computer graphic software packages.
Whatever the software used some principles should probably be respected. We should avoid three dimensional graphs. They do not improve communication and they are not easier to interpret, rather the opposite. Colours should be selected according to complementary colour criteria. Many software programmes do not allow the user to construct histograms. What is frequently called a histogram is in fact a bar graph. Units and scales on the x and y axes are not always clear in some of the software packages. Most software does not allow users to create a standard epidemic curve with one square representing one case. Particularly when the x-axis illustrates time, most of the software programmes are not flexible enough to comply with what epidemiologists need.
Personal productivity tools are commercial products designed to handle standard computing tasks such as word processing, numerical analysis, data manipulation and storage, and data presentation. Typical products include :
- Word processing software is designed to create documents such as letters, reports, and manuscripts. MS Word, WordPerfect, and Word Pro are some examples of word processing products.
- Spreadsheets, used to organize information, are very useful for handling tabular data. Addition, subtraction, division, multiplication and totaling can be done very quickly, and all results can be automatically recalculated later if new data are inserted. Formatting and graphing facilities are used to aid analysis and presentation. Well-known spreadsheet packages are MS Excel and Lotus 123.
- Database packages make it easy to organize and store data in a uniform fashion. Data can be quickly and systematically searched, sorted and presented. MS Access and Lotus Approach are database packages.
- Presentation packages are used to illustrate discussions and lectures. MS PowerPoint and Lotus Freelance are examples of presentation packages.
1. Statistics Canada, Power from data! - The computer industry