Data Visualization PDF

Data Visualization Session 2 – Part 1 Think about the nature and purpose of the visualization Consider the data/information Is it conceptual or data-driven, that is, that Ihave and want to visualize am I considering ideas or statistics? Consider the output that...

Data Visualization Session 2 – Part 1 Think about the nature and purpose of the visualization Consider the data/information Is it conceptual or data-driven, that is, that Ihave and want to visualize am I considering ideas or statistics? Consider the output that will best Do Iwant to declare or explore display the data/information something? Conceptual (ideas) vs data-driven (statistics) Figure 1 - The Gartner Hype Cycle  Illustrates a conceptual idea Figure 2 -The 2023 Gartner Hype Cycle for Emerging Technologies  Gives information about how innovations are positioned in the Hype Cycle Declarative vs explorative visualizations Declarative visualizations Declare (communicate) information to make a statement E.g., to show the quarterly sales of a company Explorative visualizations Explore data to figure something out E.g., to understand why the sales teams’ performance decreased over the past few years BERINATO, S. 2016. Visualizations That Really Work. Harvard Business Review https://hbr.org/2016/06/visualizations-that-really-work. Toshow comparisons Bar chart Line graph Box and whisker plot  Ǫuarterly Sales per Region EUR 30 000 Bar charts EUR 25 000 The primary variable is categorical – it EUR 20 000 represents the categories that are being compared The secondary variable is numerical – it EUR 15 000 is plotted on an axis with a discrete value scale EUR 10 000 EUR 5 000 EUR 0 Ǫ1 Ǫ2 Ǫ3 Ǫ4 Lille Arras Paris Bar charts Comparing the height of each bar gives A bar chart can also be extended into a a more intuitive perception than looking clustered bar chart to include more at the data in the table categories of data Line graphs History of Stock Prices $1 000,00 $ 900,00 Lines show changes in quantitative values across a continuous measurement, e.g., $ 800,00 over time Movement of the line (up or down) shows $ 700,00 positive and negative changes Overall trends are exposed to help make $ 600,00 apple predictions or projections microsoft Closing nvidia $ 500,00 google amazon meta $ 400,00 $ 300,00 $ 200,00 $ 100,00 $ 0,00 05/23 06/23 07/23 08/23 09/23 10/23 11/23 12/23 01/24 02/24 03/24 04/24 Box (and whisker) plots Boxes and lines (whiskers) show the distribution of values of one or more groups of numeric data through their quartiles The positions where the box and whisker end indicate where most of the data lie Lines extend from each box to capture the range of the remaining data, with dots placed past the edges to indicate outliers Box plots can be drawn vertically or horizontally Toshow correlations Scatter plot Heatmap  Olympics Athletes by Height and Weight 150 Scatter plots 125 Weight (in kilograms) One point for each variable are positioned 100 on two axes to show values on two numeric variables It demonstrates the relationship between 75 plotted variables (i.e., a strong / weak or positive / negative or linear / non-linear correlation) and show outlier points and/or 50 possible gaps in data The horizontal axis shows the independent variable 25 1,5 1,6 1,7 1,8 1,9 2,0 2,1 2,2 The vertical axis shows the dependent Height (in meters) variable Basketball Triathlon Volleyball How to use a scatter plot Cost per mile by miles driven $3.00 Cost per mile Do not overplot, i.e., do not plot data points $2.50 that overlap to the degree where it is difficult to see relationships between points and $2.00 variables Carefully consider the interpretation of a $1.50 AVG scatter plot – correlation does not necessarily imply causation! $1.00 $0.50 $0.00 0 1,000 2,000 3,000 4,000 Miles driven per month Heatmaps Rows are typically one category, with labels displayed on either side; and columns are another category, with labels displayed at the top or bottom Individual rows and categories are divided into subcategories Cells are intersections of the rows and columns and can contain either categorical or numerical data How to use a heatmap Table Heatmap Visualize data through variations in coloring LOW-HIGH Cross-examine multi-variate data by placing A B C A B C variables in rows and columns and coloring Category 1 15% 22% 42% Category 1 15% 22% 42% cells within the table Category 2 40% 36% 20% Category 2 40% 36% 20% Reveal patterns, displaying whether Category 3 35% 17% 34% Category 3 35% 17% 34% variables are similar to each other, and Category 4 30% 29% 26% Category 4 30% 29% 26% detect potential correlations Category 5 55% 30% 58% Category 5 55% 30% 58% Category 6 11% 25% 49% Category 6 11% 25% 49% Toshow distribution Histogram Map Histograms Similar to a bar chart, but used to group numbers into ranges The height of each bar shows how many items fall into each range You must decide 1) what are the logical ranges to use; and 2) how many bins to include It displays the frequency of the data values and can thus help to determine a data set’s median and distribution, as well as gaps or outliers It can display continuous data or categorical data Maps Represent data if some of the variables related to geographical areas Maps are eye-catching and allows for clear and intuitive data expression Toshow composition Area chart Stacked bar chart Area charts Use both lines and filled areas to convey information Effectively showcase data trends and variations over a period or across categories The x-axis represents the time intervals or categories The y-axis represents the quantitative values of the data https://www.fusioncharts.com/area-charts How to use an area chart Show different trends over time when: Data are expressed as a total There are time periods to compare The chart aims to communicate an overall trend, not individual values There are multiple data series with part-to-whole relationships, or a cumulative series of values Be careful – area charts can be misleading (such as this one) Best practices for area charts: Limit the number of data sets Keep small values in front, with simple chart areas Start the y-axis scale at zero https://www.spotfire.com/glossary/what-is-an-area-chart  Stacked bar charts Survey results Strongly Disagree | Disagree | Neutral | Agree | Strongly Agree Percent of total 0% 20% 40% 60% 80% 100% Compare total values across categories Survey item A Also shows the relative composition of each primary bar based on the levels of a second Survey item B categorical variable Survey item C The bars can be stacked horizontally or vertically; or indicated as a percentage Survey item D Survey item E Maintain a zero baseline Correctly order the category levels Order the bars from largest to smallest (unless there is an intrinsic order of levels) Session 2 – Part 2 Data storytelling… Supports effective business decision-making through… Insight Understanding Intelligence Because… …it grabs your attention… …takes you on a journey… …evokes an emotional response… https://www.juiceanalytics.com/writing/exploratory-vs-explanatory-understanding-the-difference-between-data-analysis-and-data-presentation THREE If you had only three minutes to tell your audience MINUTE what they need to know, what STORY would you include? Knaflic (2015). Storytelling with Data: A Data Visualization Guide for Business Professionals. The Big Idea must: 1. Articulate your unique point of THE view 2. Convey what’s at stake BIG 3. Be a complete sentence IDEA Duarte (2010). Resonate: Present Visual Stories that Transform Audiences. Data storytelling Understand the narrative arc in data storytelling Setup (beginning) – to explain the situation Conflict (middle) – that changed the reality Every good story includes a: Resolution (end) – created by the change that was introduced, resulting in a new reality Which stories are bad (and boring)? A series of disconnected events without a clear overarching purpose The rambling plot or direction The endless buildup (or abrupt A lack of resolution that renders the buildup of the story pointless ending) A disjointed and confusing narrative without clearly defined ideas The confusing structure that link to the main (overarching) vision Too many elements that detract from the main storyline and reduce The overstuffed plot the story’s overall coherence The lack of stakes (risk factors) No real dangers, challenges, or consequences… An example… "The COVID-16 Pandemic: A Global Impact Analysis" Start with a powerful statistic or anecdote: “In December 201G,a novel coronavirus emerged in Wuhan, China, rapidly evolving into a global pandemic that would alter the course of history” Give the context: “COVID-1G, caused by the SARS-CoV-2 virus, spread across the globe within months, leading to unprecedented public health challenges” Introduction Show maps and graphs depicting the initial spread of the virus from Wuhan to other parts of China and then globally… indicating that… “Within weeks, the virus had reached nearly every continent, with cases reported in major cities worldwide” Use a timeline to illustrate how different countries responded with lockdowns, travel bans, and social distancing measures…indicating that… “Governments worldwide implemented various Rising action strategies to contain the spread, ranging from strict lockdowns to aggressive testing and contact tracing” Present data about the healthcare impact…indicating that… “Healthcare systems were overwhelmed, with hospitals running out of ICU beds and medical supplies” Present data (e.g., charts about unemployment rates, stock market fluctuations,...) that show the economic consequence…indicating that… “The pandemic triggered a global economic Rising action downturn, with millions losing their jobs and businesses shutting down” Present the key turning point: vaccine development: highlight the race to develop vaccines, with timelines, trial phases, efficacy rates… indicating that… “In an unprecedented scientific effort, vaccines were developed in record time, with X companies, leading the way with X technology” Climax Show how the resolution begins… with vaccine distribution and the emergence of variants…indicating that… “While high-income countries achieved high vaccination rates quickly, many low- and middle-income countries faced significant distribution challenges” and “New variants like X and X posed ongoing challenges, necessitating booster doses and continued public Falling health measures” action Assess the impact…in terms of health outcomes, economic recovery…e.g., “The pandemic underscored the need for global cooperation in public health,research, and resource distribution” Give the lessons learnt…in terms of global cooperation, preparedness for future pandemics… Resolution An example… “The COVID-16 Pandemic: A Global Impact Analysis” Visualization tools and techniques to use… Maps and geographic data – to show the spread of the virus geographically Timelines – to depict the progression of events and responses Charts and graphs – for economic data, infection rates, vaccination rates, etc. Infographics – to summarize key points and make complex data accessible https://ourworldindata.org/covid-cases Beginning (setup) When? Where? Who? – the main “character” The problem? – the imbalance to be fixed The action? – what must happen/ change The solution? – how should the change be implemented Middle (conflict) Develop the problem situation – give relevant background info Include external context and/or comparison points Give examples that illustrate the problem Include data that demonstrates the problem Articulate what will happen in case of no action Discuss potential options to address the problem Illustrate the benefits of the recommended solution(s) Clearly state why your audience is in a unique position to take a decision and/or action End (resolution) Emphasize the call to action – what do you want your audience to do with the new understanding and knowledge given to them Don’t underestimate the power of (subtle) repetition The story must be clear! Horizontal logic The titles of your slides give an idea of the overarching story Vertical logic All the information on each slide is self-reinforcing, i.e., the title, visuals, words, etc. reinforce each other Let a friend/colleague give you a fresh perspective