Chapter 76 How to Give a Presentation

Data Scientists are often asked to present their work. This could be in a meeting with other co-workers or at a large conference amongst colleagues with similar interests. Regardless of where you’re presenting, there are general and important guidelines to consider when preparing the materials for your presentation.

In this lesson we’ll cover what to consider when preparing a slide presentation, guidelines for creating good slides, and tips for presenting material well. This lesson is largely based off of our experiences and the tips from Zach Holman. Links to his work directly can be found at the end of this lesson.

This lesson will be focused on how to give effective slide presentations, like what you could generate in Google Slides. These guidelines, however, will likely prove beneficial for any oral or visual presentation you may have to give as a data scientist.

76.0.1 Presentation Goals

Generally, there are three goals of any presentation. A good presentation should inspire, educate, and entertain. Those listening to your presentation should leave the room feeling like they learned something, with the urge to try something new, and having enjoyed learning whatever it is you presented. If those three goals are accomplished, you have without a doubt delivered a stellar presentation.

Presentation Goals

76.0.2 Know your Audience

In order to inspire, educate, and entertain, the first thing you must consider is your audience. For presentations, people often say you must know your audience. If you have a room full of analytical people (mathematicians, accountants, scientists, etc.), you should consider presenting data and numbers. Conversely, if you are presenting to a room full of creatives (artists, photographers, writers, etc.), it’s likely best to ensure that the graphics you present are visually appealing. You should always keep your audience in mind while preparing a presentation.

76.0.3 Mind your Audience

After considering your audience and designing your presentation to be most appropriate for those listening, you must always stay within your allotted time. Out of respect for the time of others in the room and for others who may also have information to present, this is essential. If you have 5 minutes to talk, stop at or before 5 minutes. If you have 20 minutes to speak, stop at or before 20 minutes. Your audience will tune out if you go over your time limit or you’ll be told to stop by someone else in the room. It’s best to avoid either of these situations and respect the time of those in your audience. Always stay within your allotted time.

76.0.4 Prepare

Putting together a good presentation takes time. Be sure to leave yourself enough time to put a good story and beautiful slides together.

76.0.5 Tell a Story

With those goals and your audience in mind, you’re ready to start considering how you’re going to go about presenting information to your audience. As mentioned in a previous lesson, when you’re giving a presentation, you’re telling a story.

When presenting, you’re telling a story with and introduction, a middle, and an end. It’s best to outline your presentation before you start preparing slides. This includes jotting down or at the very least thinking about what you’ll convey to your audience and how you’ll make it into a story. You may consider a number of questions: What story do you want to tell? What do you want to convey in your introduction? What pieces are necessary to the story to be included in the middle? What do you want your listeners to take away from your presentation? How will you include this information in your conclusion? All of these are good questions to consider when outlining your talk.

Outline your presentation

Finally, as Zach Holman explained in his talk on talks, the best talks are stories and the best stories use repetition. It’s ok to repeat important information to your audience. Don’t be afraid of repeating yourself to make a point clear to your listeners.

76.0.6 Slide Design

Now that you’ve outlined what you’ll talk about in your presentation, it’s time to decide how you’re going to put those ideas onto slides. There are many things to consider when designing visually-appealing slides. We’ll discuss the most important in this lesson.

76.0.6.1 Text

A few guidelines when deciding the words you’ll include on slides:

  • limit the number of ideas on a single slide
  • limit words on slides
  • encourage listening (limit reading)
  • include references on the slides directly (and at the end!)

Do not try to cram all your ideas onto a single slide. And, everything you say does not have to be up on the slides. You’re speaking for a reason. The slides should help guide you along in telling your story, but your audience should have to listen to what you’re saying to get the full picture of your story.

76.0.6.1.1 Fonts

To convey textual information to your audience, choosing a good font is important. It’s generally safe to stick to Sans Serif font. Sans Serif fonts can be searched through at Google Fonts. And, when in doubt, Helvetica is a safe font choice. Further, use consistent fonts throughout your talk. More than one font can be used to draw viewers attention to something, but typically there should be a consistent font used throughout the presentation. Finally, as with most rules, there are exceptions, so take time deciding on what font looks best for each part of your presentation.

Choose Good Fonts

76.0.6.1.2 Size

Regardless of what font you choose for your text, your text should be very large. It’s often argued that you should design your slides for the back of the room.

Use Large Text

The same goes for images. There’s no need to leave empty space on your slides around images. Expand your images to take up as much space on the slide as possible.

Expand Images

76.0.6.2 Colors

Finally, with regards to slide design, colors matter. Choosing a dark background (such as dark gray) means that your text should be light (maybe white). If your background is light, your text should be dark. Contrast will make it easier on your audience to read.

Choose Good Colors

Additionally, use color to focus on text you want your audience to focus in on. If all your text is white, highlight a few words in a brighter color to draw your listener’s attention to what’s important.

Highlighting Text

The same goes for figures and plots. All images should have colors that are viewable and distinguishable by every person in your audience. Consider color blindness. Consider colors that tend not to project well (such as yellows or light pastels). Then, design your slides using colors that will work for your audience.

76.0.6.3 Alignment

Visually, things should be aligned. Center things in the middle of your slide. Make sure text boxes that should line up do line up. It may seem trivial, but it’s important to line things up so viewers aren’t distracted by something like alignment and can instead focus on your talk.

Prioritize alignment

76.0.7 Presenting

When it comes time to give the presentation, there are a few things to keep in mind. First and foremost, speak clearly. Whether you are a loud-talker, a soft-speaker, someone who speaks slowly, or a fast-talker, the most important thing is to make sure that the words you say are clear to your audience.

Second, you should be excited. If you’re not excited or passionate about what you’re talking about, why would your audience be? If you’re not excited, it may be best to reconsider your outline and re-work your story until you are.

To avoid being boring during your talk, you can vary the speed and volume of your voice. You can move around so you’re not always in one place. And, you can use pauses effectively. It’s ok to not speak every second that you’re up there. You can pause and give your audience some time to look at a graph before you talk about it. Silence for short periods of time is allowed!

Finally, be yourself. If you naturally like to tell jokes, tell jokes during your presentation. If stories are more your style, work a story or two in. Ultimately, if you’re not comfortable in front of your audience, check to make sure you’re being true to who you are as an individual.

Presentation Tips

Finally, when presenting it’s important to remember that you’ve seen the data and figures you’re presenting many times, but your audience has not. They’ll need time to get up to speed! Thus, it’s important to always introduce your axes (tell your audience what is on the x-axis and what is on the y-axis), explain the colors on your plot, and walk the audience through the figure you’re presenting.

Explain Your Figures

76.0.8 Practice

Most people are hesitant when it comes to speaking. They’re nervous about getting up in front of a crowd. If you find yourself being nervous to make a data science presentation, know that you’re not alone.

For those who are nervous to speak publicly, nerves may never go away completely, but there are ways to limit your nerves. Practicing your presentation is one of the best ways to limit nerves during your presentation. You should present out loud to yourself. Recording yourself and listening can help too (even if it is sometimes painful)!

In addition to limiting your nerves, practicing will help you figure out the best way to explain the details included in your presentation and will ensure that your presentation does not take more time than you have been allotted.

The further along you are in your career, the less you will likely have to practice before presentations. However, as you get started, practicing is the best preparation for giving a talk!

Practice. Practice. Practice.

76.0.8.1 Be Prepared

The day of your presentation, things may go wrong. Power goes out, projectors don’t always present your material exactly the same way it looks on your computer screen. Technology doesn’t always behave as we expect it too. In these cases, you just have to roll with the punches.

To avoid any big issues, it’s best to bring a copy of your talk on a USB drive, carry any adapters you may need should you have to (or choose to) present from your own computer. Don’t expect the location to have the adapter you need. And, be sure your phone is on silent. After that, just roll with anything that goes wrong. The audience will be forgiving, as they all know that technology can sometimes act unexpectedly.

Prepare & then roll with the punches

76.0.9 Handling Questions

After your presentation, there may be time allotted for the audience to ask questions. When answering questions, always take a little bit of time to pause and think about the question before answering. In fact, it’s often helpful to repeat the question asked of you back to the audience. This ensures that the entire room has heard the question and gives you some time to think. If you need more time, remember, silence is ok! Finally, if you don’t know an answer, it’s ok to say “I don’t know.” You should never make up an answer because you’re afraid of saying “I don’t know.”

Q&A Tips

76.0.10 Example Presentation: Analysis

Often, as a data scientist, you’ll be tasked with presenting an analysis you’ve done. To do so, you’ll want to use the same guidelines previously discussed in this lesson, but with a focus on presenting the story of your data analysis. This includes the plots, analytical approach, and findings of your project. That said, your slides should still be well-designed, you should still tell a story, and your text and colors should all be readable when projected; however, in this case, there are a few additional caveats to consider.

To discuss these, we’ll use an example presentation from Julia Silge, who is a data scientist at Stack Overflow and a wonderful presenter. In 2017 at the rstudio::conf, Julia Silge presented “Text Mining the tidy Way”. The video and visuals from her presentation are available online. This talk discusses the tidytext package (which she and David Robinson developed) and example analyses using this awesome R package. We’ve discussed this package previously, but if you want a refresher on tidytext, how to work with textual data, and sentiment analysis, this is a great resource!

As above, we’ll highlight a few slides from the talk and discuss considerations to make when presenting a data analysis.

76.0.10.1 Talk Outline

As in Lucy’s talk, Julia Silge, in addition to an introduction and a conclusion, had three main parts to her talk:

  • tidytext package
  • Jane Austen example
  • NASA example

In data analysis talks, it’s often best to start with background information. Julia covers this information when discussing what the tidytext package is. Then, she delves into discussing a few examples of the types of analyses you can do with this package.

76.0.10.2 Slide Design

As discussed above with Lucy’s presentation, in Julia’s slides, she limits the amount of information she puts on any one slide, thus allowing the audience to listen to the words she’s saying. And, she has text that’s large enough and legible when projected.

However, what’s different about this presentation is how Julia presents her analyses. When presenting an analysis, it’s generally best to first explain the approach and then present the results. For example, Julia uses TF-IDF to analyze text in Jane Austen’s novels.

She first explains what TF-IDF is. She includes the bare minimum amount of information on her slide, so that her audience is only seeing what’s necessary. Then, she verbally describes what TF-IDF is.

TF-IDF slide

On subsequent slides she includes the code she used to run the analysis, discussing what is going on with the code on each slide and describing the output.

code to run TF-IDF

Finally, for each part of her analysis, she includes a visualization of the results. These figures have text large enough to be seen by all in the audience, are well-labeled, and include an informative title.

figures from analysis

Note that Julia does not go into every single detail of every analysis, nor just she talk about all the things she tried in a single presentation. She includes enough information so that her audience learns and can go try this type of analysis on their own, if they’re interested!

76.0.10.3 Presentation

Watching the 18 minute video will give you the best sense of how Julia presented the information in her tidytext presentation; however, we’ll highlight a few things here.

video for Julia’s presentation

Julia spoke at a reasonable pace and clearly, keeping her audience interested. Additionally, she presented true to her personality. Julia and Lucy are two different people and that is clear in their presentation styles. Differences are wonderful and help keep presentations interesting! It would be boring if everyone were the same.

Additionally, Julia knew her audience. She knew that there would be many programmers in her audience, and that most of them would be familiar with the R programming language. Thus, she didn’t need to explain what the R syntax was. She could put R code on her slides, and her audience would successfully follow along. But, she knew that not everyone has worked with the tidytext package. Thus, she focused her time here, discussing the purpose of and basics on how to use the tidytext package and provided clear examples of analyses using this package. When outlining and preparing presentations, always consider your audience. If your audience is more technical, include more details about how you did the analysis. If they’re less technical, be sure to explain what you did at an appropriate level. And, of course, always make sure your figures are clear, regardless of your audience.

Additionally, we’ll note that at around 17:45 in the presentation, Julia went to show an image but it didn’t immediately show up how she had intended. This is a great example of rolling with the punches. She didn’t panic. She simply acknowledged that it didn’t work the first time and tried again. The audience, of course, didn’t mind, but when you’re presenting, these small occurrences can feel like a big deal. When it happens to you in the future, know that things don’t always work as anticipated and that this happens to everyone. If this happens to you, take a play out of Julia’s book and simply acknowledge what happened, try again, and continue on!

Julia keeps her cool

76.0.11 Summary

In this lesson we’ve discussed the important pieces to designing and presenting your data analysis project. Always be mindful of your audience, create good slides, and present your ideas clearly. Practicing your presentations will help, especially when you’re first giving talks.

76.0.12 Additional Resources

76.0.12.2 Presentation Examples

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