We create a diverging stacked bar chart to plot a 5 point Likert scale. There a lots of ways to plot a Likert scale but according to Robbins & Heiberger, a diverging stacked bar chart is the best and I agree.
I've used D3.js. There is also an R package by Robbins & Heiberger.
The original can be found at github
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Diverging Stacked Bar Chart with D3.js</title> | |
| <style> | |
| body { | |
| font: 10px sans-serif; | |
| } | |
| .axis path, | |
| .axis line { | |
| fill: none; | |
| stroke: #000; | |
| shape-rendering: crispEdges; | |
| } | |
| </style> | |
| <script src="http://cdnjs.cloudflare.com/ajax/libs/d3/3.4.13/d3.min.js"></script> | |
| <body> | |
| <div id="figure" style="margin-bottom: 50px;"></div> | |
| <script> | |
| var margin = {top: 50, right: 20, bottom: 10, left: 65}, | |
| width = 800 - margin.left - margin.right, | |
| height = 500 - margin.top - margin.bottom; | |
| var y = d3.scale.ordinal() | |
| .rangeRoundBands([0, height], .3); | |
| var x = d3.scale.linear() | |
| .rangeRound([0, width]); | |
| var color = d3.scale.ordinal() | |
| .range(["#c7001e", "#f6a580", "#cccccc", "#92c6db", "#086fad"]); | |
| var xAxis = d3.svg.axis() | |
| .scale(x) | |
| .orient("top"); | |
| var yAxis = d3.svg.axis() | |
| .scale(y) | |
| .orient("left") | |
| var svg = d3.select("#figure").append("svg") | |
| .attr("width", width + margin.left + margin.right) | |
| .attr("height", height + margin.top + margin.bottom) | |
| .attr("id", "d3-plot") | |
| .append("g") | |
| .attr("transform", "translate(" + margin.left + "," + margin.top + ")"); | |
| color.domain(["Strongly disagree", "Disagree", "Neither agree nor disagree", "Agree", "Strongly agree"]); | |
| d3.csv("raw_data.csv", function(error, data) { | |
| data.forEach(function(d) { | |
| // calc percentages | |
| d["Strongly disagree"] = +d[1]*100/d.N; | |
| d["Disagree"] = +d[2]*100/d.N; | |
| d["Neither agree nor disagree"] = +d[3]*100/d.N; | |
| d["Agree"] = +d[4]*100/d.N; | |
| d["Strongly agree"] = +d[5]*100/d.N; | |
| var x0 = -1*(d["Neither agree nor disagree"]/2+d["Disagree"]+d["Strongly disagree"]); | |
| var idx = 0; | |
| d.boxes = color.domain().map(function(name) { return {name: name, x0: x0, x1: x0 += +d[name], N: +d.N, n: +d[idx += 1]}; }); | |
| }); | |
| var min_val = d3.min(data, function(d) { | |
| return d.boxes["0"].x0; | |
| }); | |
| var max_val = d3.max(data, function(d) { | |
| return d.boxes["4"].x1; | |
| }); | |
| x.domain([min_val, max_val]).nice(); | |
| y.domain(data.map(function(d) { return d.Question; })); | |
| svg.append("g") | |
| .attr("class", "x axis") | |
| .call(xAxis); | |
| svg.append("g") | |
| .attr("class", "y axis") | |
| .call(yAxis) | |
| var vakken = svg.selectAll(".question") | |
| .data(data) | |
| .enter().append("g") | |
| .attr("class", "bar") | |
| .attr("transform", function(d) { return "translate(0," + y(d.Question) + ")"; }); | |
| var bars = vakken.selectAll("rect") | |
| .data(function(d) { return d.boxes; }) | |
| .enter().append("g").attr("class", "subbar"); | |
| bars.append("rect") | |
| .attr("height", y.rangeBand()) | |
| .attr("x", function(d) { return x(d.x0); }) | |
| .attr("width", function(d) { return x(d.x1) - x(d.x0); }) | |
| .style("fill", function(d) { return color(d.name); }); | |
| bars.append("text") | |
| .attr("x", function(d) { return x(d.x0); }) | |
| .attr("y", y.rangeBand()/2) | |
| .attr("dy", "0.5em") | |
| .attr("dx", "0.5em") | |
| .style("font" ,"10px sans-serif") | |
| .style("text-anchor", "begin") | |
| .text(function(d) { return d.n !== 0 && (d.x1-d.x0)>3 ? d.n : "" }); | |
| vakken.insert("rect",":first-child") | |
| .attr("height", y.rangeBand()) | |
| .attr("x", "1") | |
| .attr("width", width) | |
| .attr("fill-opacity", "0.5") | |
| .style("fill", "#F5F5F5") | |
| .attr("class", function(d,index) { return index%2==0 ? "even" : "uneven"; }); | |
| svg.append("g") | |
| .attr("class", "y axis") | |
| .append("line") | |
| .attr("x1", x(0)) | |
| .attr("x2", x(0)) | |
| .attr("y2", height); | |
| var startp = svg.append("g").attr("class", "legendbox").attr("id", "mylegendbox"); | |
| // this is not nice, we should calculate the bounding box and use that | |
| var legend_tabs = [0, 120, 200, 375, 450]; | |
| var legend = startp.selectAll(".legend") | |
| .data(color.domain().slice()) | |
| .enter().append("g") | |
| .attr("class", "legend") | |
| .attr("transform", function(d, i) { return "translate(" + legend_tabs[i] + ",-45)"; }); | |
| legend.append("rect") | |
| .attr("x", 0) | |
| .attr("width", 18) | |
| .attr("height", 18) | |
| .style("fill", color); | |
| legend.append("text") | |
| .attr("x", 22) | |
| .attr("y", 9) | |
| .attr("dy", ".35em") | |
| .style("text-anchor", "begin") | |
| .style("font" ,"10px sans-serif") | |
| .text(function(d) { return d; }); | |
| d3.selectAll(".axis path") | |
| .style("fill", "none") | |
| .style("stroke", "#000") | |
| .style("shape-rendering", "crispEdges") | |
| d3.selectAll(".axis line") | |
| .style("fill", "none") | |
| .style("stroke", "#000") | |
| .style("shape-rendering", "crispEdges") | |
| var movesize = width/2 - startp.node().getBBox().width/2; | |
| d3.selectAll(".legendbox").attr("transform", "translate(" + movesize + ",0)"); | |
| }); | |
| </script> | |
| </body> | |
| </html> |
| Question | 1 | 2 | 3 | 4 | 5 | N | |
|---|---|---|---|---|---|---|---|
| Question 1 | 24 | 294 | 594 | 1927 | 376 | 3215 | |
| Question 2 | 2 | 2 | 0 | 7 | 0 | 11 | |
| Question 3 | 2 | 0 | 2 | 4 | 2 | 10 | |
| Question 4 | 0 | 2 | 1 | 7 | 6 | 16 | |
| Question 5 | 0 | 1 | 3 | 16 | 4 | 24 | |
| Question 6 | 1 | 1 | 2 | 9 | 3 | 16 | |
| Question 7 | 0 | 0 | 1 | 4 | 0 | 5 | |
| Question 8 | 0 | 0 | 0 | 0 | 2 | 2 |
