Avoiding Distortion and Misuse of Visuals Presented by Nicole Onyeneho October 12, 2004

Outline What is a Visual? What is a Visual? Problems Associated With Visuals Problems Associated With Visuals Causes of Misuse and Distortion of Visuals Causes of Misuse and Distortion of Visuals Ways to Avoid Distortion of Data Ways to Avoid Distortion of Data

What is a Visual? A visual is a piece of illustrative material. A visual is a piece of illustrative material. A photograph, picture, chart, or graph that displays information or promotional material in a way that appeals to the eye *A photograph, picture, chart, or graph that displays information or promotional material in a way that appeals to the eye * *MSN Encarta (

Problems Associated With Visuals Visuals can distort a reader’s perception of the material Visuals can distort a reader’s perception of the material Must avoid unintentionally misrepresenting the information you are presentingMust avoid unintentionally misrepresenting the information you are presenting

Causes of Distortion and Misuse of Visuals Careless data collection Careless data collection Inaccurate data presentation Inaccurate data presentation

Ways to Avoid Distortion of Data Utilize a random testing sample that is sufficiently large Utilize a random testing sample that is sufficiently large For example, results that state a nonprescription medication relieves pain in 90% of users sounds impressive, but neglects the fact that only 10 people were included in the sampleFor example, results that state a nonprescription medication relieves pain in 90% of users sounds impressive, but neglects the fact that only 10 people were included in the sample

Ways to Avoid Distortion of Data Design questions to elicit unambiguous responses Design questions to elicit unambiguous responses Record and present ALL data, even that which is unfavorable Record and present ALL data, even that which is unfavorable Make sure that data measures what is claimed to be measured Make sure that data measures what is claimed to be measured Make sure that cause-effect relationships are logical Make sure that cause-effect relationships are logical

Ways to Avoid Distortion of Data Ensure that measures of central tendency are used correctly Ensure that measures of central tendency are used correctly Mean – the arithmetic average; the numerical result obtained by dividing a sum by the number of quantities addedMean – the arithmetic average; the numerical result obtained by dividing a sum by the number of quantities added Median – the middle number in a series of numbersMedian – the middle number in a series of numbers Mode – the value or number that occurs most frequently in a seriesMode – the value or number that occurs most frequently in a series

Inaccurate Data Presentation Once accurate and complete data have been collected, care must be taken in choosing the manner of presentation, as that can also be distorted Once accurate and complete data have been collected, care must be taken in choosing the manner of presentation, as that can also be distorted Make sure that numbers and percentages match the conclusionsMake sure that numbers and percentages match the conclusions Consider all the variable involved when extending or projecting dataConsider all the variable involved when extending or projecting data

Inaccurate Data Presentation Selecting the appropriate type of figure is important Selecting the appropriate type of figure is important The purpose of the figure must be considered in choosing type so that significant information is conveyed effectivelyThe purpose of the figure must be considered in choosing type so that significant information is conveyed effectively Two types of graphs often unnecessarily distort dataTwo types of graphs often unnecessarily distort data Line graphs Line graphs Pictorial graphs Pictorial graphs

Avoiding Distortion of Line Graphs Begin the quantitative scale (usually the y-axis) at zero Begin the quantitative scale (usually the y-axis) at zero Differentiate lines on a graph by varying the type of line used Differentiate lines on a graph by varying the type of line used Different colored lines can not be distinguished in a photocopied documentDifferent colored lines can not be distinguished in a photocopied document Do not change the proportion of the grid by distorting the relationship between the axes Do not change the proportion of the grid by distorting the relationship between the axes

Avoiding Distortion of Pictorial Graphs Avoid using fractions of isotypes (the symbols used on a pictorial graph) Avoid using fractions of isotypes (the symbols used on a pictorial graph) Use isotypes of the same size for the same graph Use isotypes of the same size for the same graph

Could Your Presentation Be Misleading to Readers? Does the visual clarify, explain, or support the text? Does the visual clarify, explain, or support the text? Will the reader know the source of the data? Is the source authoritative? Will the reader know the source of the data? Is the source authoritative? Is the sample for collected data randomly selected? Is the sample for collected data randomly selected? Are all of the necessary collected data included? Are all of the necessary collected data included? Are irrelevant data omitted? Are irrelevant data omitted? Is the visual completely labeled: number, title, caption? Is the visual completely labeled: number, title, caption? Are variables and scales accurately labeled? Are variables and scales accurately labeled? Is the quality of the visual the highest possible? Is the quality of the visual the highest possible? Is the visual easy to understand? Is the visual easy to understand? Does the conclusion logically follow from the data? Does the conclusion logically follow from the data?

Conclusion If you can offer affirmative responses to all of the previous questions, then you have successfully put together a coherent presentation If you can offer affirmative responses to all of the previous questions, then you have successfully put together a coherent presentation