Slide decks

A slide deck presents information visually for a particular audience and purpose. Live presentation, self-study and reference use require different amounts of detail, but all depend on clear organisation, legible content and consistent design.

Purpose, audience and requirements

Professional design matters whether a deck supports the writer's own presentation or is prepared for a client. ¹ Slide decks include congress presentations, live workshop or webinar materials, agency pitches, self-guided learning and reference collections such as study-report outputs. ^{2, 3, 4}

The name “slide” came from framed photographic transparencies moved through a projector; frames could be cardboard, metal or plastic. ⁵ A revolving tray later allowed instructors to retain collections and project them continuously while speaking, establishing slides as a standard audiovisual format. ⁵

Three questions establish the design brief: ⁶

• Does the programme introduce a new subject or technique, present a viewpoint or review information?
• Who will view it, and how familiar are they with the subject?
• Will it be projected in a large hall, viewed on classroom computers or used in another setting?

⁶

A slide effective for one combination of purpose, audience and setting may not work for another. ^{6, 5} Live slides have limited viewing time and need less content, while self-guided or reference slides can carry more detail for readers who control the pace. ^{7, 8} Even when readers have more time, a complex slide should be made simpler and easier to read where possible. ⁹

In a January 2020 webinar poll allowing multiple answers, respondents reported working on live-learning decks (65%), reference decks (45%), self-guided learning (37%) and agency pitches (17%). ^{2, 4, 7}

The brief should establish any style guide, guidelines and restrictions before design begins; client requirements govern choices such as bullets, title capitalisation, colours and logos. ^{10, 11, 12, 13} Congress instructions specify what presenters should and should not do, and decks need acknowledgments and declarations of interests. ¹⁴ Public-facing decks should be checked for applicable requirements on references, acknowledgments and clinical-trial identifiers. ¹⁴

Content and slide count

A fixed rule of one slide per minute does not account for content density: twenty sparse slides may fit ten minutes and be easier to absorb than ten crowded ones. ¹⁵ A contrasting warning concerns slides with five lines or points: one per minute leaves only about twelve seconds per item and can force the presenter to rush or skip content. ¹⁶ The appropriate count is the number that can be covered comfortably in the allotted time. ¹⁵ One example used about 130 slides for approximately 35 minutes of speaking because many passed quickly. ¹

Each live slide should usually convey one simple point, using minimal text, omitting irrelevant material and preferring a visual where it communicates the message. ^{17, 18, 19} A crowded slide on advisory-board meeting reports became three clearer slides covering principles, things to avoid and planning. ²⁰ If the client requires a complex slide, that constraint remains, but splitting it into simpler slides should be considered. ^{21, 9}

Paragraphs can be placed in speaker notes rather than projected; an important quotation may justify a paragraph on a slide, but paragraphs and bullet lists should not be the default for an entire deck. ¹⁸ More digestible chunks may require more slides, and an overlong deck may be attempting too much. ¹⁸

Listening to a speaker, reading text and examining an image are three simultaneous inputs that can compete for attention. ²² Removing explanatory text and speaking over the relevant image can reduce that competition: in a computer-safety example, the spoken instructions conveyed the same precautions without repeating them on screen. ^{22, 23}

Common faults to remove are: ²⁴

• Slides full of text.
• Unnecessary slides.
• Words too small to read.
• Words set at different angles.
• Overcrowded slides.
• Images more detailed than the point requires.
• Poor contrast between content and background.

²⁴

A complementary template checklist recommends: ²⁵

• Making the audience's task easy.
• Avoiding information overload.
• Avoiding fonts that are too small or unreadable.
• Limiting animation and avoiding a different colour for each sentence.
• Using consistent font faces and sizes across slides.

²⁵

Headings, typography and bullets

Sans serif faces such as Arial or Calibri are a suggested choice for large slide text. ²⁶ One suggested standard is Arial 32 point for titles and 24 point for first-level bullets; smaller text becomes harder to see. ²⁶ Titles should ideally retain one font style and size and fit on one line; shortening the wording is preferable where possible to alternating sizes or using crowded two-line titles. ^{27, 28, 11} Sentence capitalisation is preferred unless a client or style guide requires otherwise, and two lines of all-capital title text can be especially difficult to read. ^{11, 12}

First-level bullets should have consistent size and style, second-level bullets may be smaller, and footnotes and references should follow consistent settings. ^{28, 25} Constraints occasionally require exceptions, but consistency should be maintained where possible. ²⁸

Bullets should preferably fit on one line and use no more than two levels. ^{17, 12, 29} Seven bullets is one suggested maximum. ³⁰ Plain bullet characters are preferable to decorative ones; a small square and a hyphen are one suggested top-level and subordinate pair. ¹²

Bullets can clarify where successive points begin, but a single piece of text in a table cell usually needs no bullet, and a quotation can stand alone with its reference immediately after it. ^{31, 32} A table can expose gaps in an argument that disconnected bullets obscure, while a flow diagram or sequentially built illustration can show a story or logical progression. ^{33, 34} Twenty consecutive bullet-list slides would provide little visual variety. ^{34, 35}

Advice for seminar slides recommends: ³⁶

• Use informative headings without repeating them across slides or restating them in the body.
• Put the main point first.
• Keep text terse, for example using noun phrases rather than complete sentences.

³⁶

Further audience-oriented advice warns that: ³⁶

• Excessive text, excessive data and type that is too small are common faults.
• Audiences should not be asked to wade through too much data on one slide.
• Footnotes can divert attention to finding the source.
• Unnecessary abbreviations can confuse, particularly when the presentation language is not the audience's first language.

³⁶

Assertion and evidence

Michael Alley's assertion-evidence format replaces a topic heading with a complete-sentence assertion and supports it with relevant visuals, bringing focus and avoiding repetitive headings. ³⁷ It differs from advice to use terse noun phrases, so these are alternative approaches rather than a single wording rule. ^{37, 36}

An example replaces “Digital Acquisition System” with “Digital data acquisition changes the data's form” and shows four stages: ^{38, 39, 40}

1. An accelerometer outputs an analogue voltage.
2. Hardware converts the analogue signal to digital.
3. A computer samples a number of points.
4. Data are exported to applications such as Microsoft Excel and Matlab.

^{38, 39, 41, 42, 43}

A second example links the question of whether Icelandic and Baltic dunlins are different subspecies to the implication that a declining Baltic population might then be a threatened subspecies. ⁴⁴ The complex visual in this example requires additional viewing time. ⁴⁴

Simple assertion-evidence slides can support a live speaker, while information-rich versions can function as self-contained teaching material requiring time for study. ^{37, 40} Complex images can be useful in computer-based or online assignments where learners control their pace; accompanying audio then supplements the visual, reversing the relationship of visual support for a live speaker. ^{37, 44}

Default topic headings and bullet lists can become monotonous and limit recall, and software should not replace understanding the relationships and relative importance of the information. ^{45, 38} PowerPoint's way of organising and summarising information has itself been criticised for shaping how a case is presented. ^{46, 47} Effective design depends on selecting a format that suits the purpose and applying audiovisual principles, rather than attributing every poor presentation to the program. ^{38, 48}

Visual variety and construction tools

Effective arrangement uses contrast, flow, hierarchy, unity, proximity and white space to establish priority; background, colour, text and images should be consistent, while movement concerns timing, pace, distance, direction and eye flow. ¹⁸ Thematically related slides can vary without looking unrelated, and assigning equal visual weight to everything undermines priority. ¹⁸

Recommendations for the frequency of visuals differ: one 2007 guideline suggested a data display about every third slide, while advice reported in 2023 recommended graphical elements on at least two of every three slides. ^{49, 29} Colour, text in shapes, differing text sizes and icons can provide interest, show importance and connect ideas. ^{50, 51} Practical PowerPoint techniques include: ⁵⁰

• Converting bullet lists to SmartArt.
• Converting SmartArt to shapes.
• Making custom SmartArt from shapes.
• Taking inspiration from Design Ideas.
• Adjusting icons.
• Adding stock photographs.

⁵⁰

Other conversions put bullet points in differently shaded vertical boxes or stretch a chevron into a timeline, adding a gradient, lines and matching icons to convey dates or events. ²⁹

As described in 2021, Office 365 supplied more SmartArt, icons and stock images and the Design Ideas function than older PowerPoint versions; older versions retained templates and SmartArt but could lack the newer resources. ^{50, 52} Canva, Piktochart and Visme also supplied templates and images, though exports could be more difficult or watermarked. ⁵⁰

Clients usually supply templates with approved palettes and layouts; when a template must be developed, a Microsoft theme can be adapted or a new one created in Slide Master. ²⁹ Built-in templates were a suggested starting point in 2007, and free Microsoft and SlideShare collections were recommended in 2014. ^{49, 25} In 2013, MedicinePPT offered about 200 downloadable medical templates as zipped .POT files, covering anatomy, doctors, medical symbols, nurses, pills, body systems, laboratory equipment and diseases, alongside paid templates. ⁵³

Spacing and alignment

Consistent positions keep consecutive text slides from appearing to jump: the intersection of the left margin and first bullet line should remain fixed as slides change. ^{54, 55, 56} A single Slide Master can maintain that position, though inherited decks may contain incompatible layouts or masters altered by many contributors. ^{57, 58}

A spacing example used a line multiple shown as 1.14, entered as 1.15, with six points between bullets; reducing the multiple to 0.9 and the paragraph spacing to zero visibly compressed the text. ^{59, 60} Text boxes and arrows also need consistent alignment, size, spacing and angles, with arrows ending at box borders rather than piercing them or stopping at inconsistent distances. ^{57, 61, 62}

The useful tools are Slide Master, alignment tools, horizontal and vertical guides, paragraph and line spacing, and Format Painter, which copies formatting between objects. ^{63, 64, 58} In a January 2020 webinar poll allowing multiple answers, with 85% of attendees voting, respondents reported confidence in paragraph and line spacing (89%), alignment tools (61%), guides (61%), Slide Master (48%) and Format Painter (46%). ^{63, 65, 64}

Backgrounds, colour and images

A slide that looks clear on a high-resolution laptop can lose contrast when projected, so the design needs to allow for poorer display conditions. ³⁰ Strong contrast is especially important when the venue cannot be checked beforehand. ^{66, 67} Dark text on a light background with a simple logo is one suggested starting point. ^{13, 19} The traditional white or yellow serif type on dark blue, or silver sans serif type on a dark background, can sometimes work, but gradient fills and pastel foregrounds or backgrounds risk losing contrast under poor projection. ⁶⁸

Red on blue and blue on red are combinations to avoid. ¹³ Large logos reduce content space and should not overlap text, while margins need to balance white space against usable room. ¹³ Colour can organise information and support flow; a six-digit hex code can specify a colour precisely, or the eyedropper can match an existing colour, such as a legend entry and its figure. ²⁹

A copied image may need recreation to achieve clear contrast and resolution; one comparison showed a blurred pasted figure beside a clearer recreated version, while acknowledging that redrawing is not always feasible. ⁶⁹ Images need enough resolution at the final displayed size, because enlargement can reveal graininess. ^{70, 71} To fill a slide, a bitmap or JPEG can be pasted and resized from its corners. ⁷¹ For a square image on a 16:9 slide, one approach is to fit its height and place it on a black background rather than stretch it to the slide's proportions. ^{72, 71}

A January 2020 webinar poll compared these text-and-image layouts: ^{73, 74, 75}

Layout	Preference
Text left, image right	39%
Text wrapping above an image on the right	9%
Text left, dividing line, image right	13%
Image left, text right	36%
None of these	3%

^{73, 74, 75}

The conventional text-left arrangement is one option; a dividing line or reversed positions can also be considered, with alignment as good as possible. ²¹

Tables, algorithms and animation

Tables can be simplified with less text, uniform column widths and consistent row heights within each block. ^{76, 77} One suggested ideal for slide tables is no more than seven rows and five columns, though achieving this can be difficult. ⁷⁷

A treatment or study algorithm can be rebuilt as a sequential display, introducing each step as it is explained, with aligned boxes and arrows ending precisely at their edges. ^{76, 78} Animation should be limited and purposeful, supporting a concept or helping the audience follow the story. ^{30, 25, 49, 29} Examples include introducing a p-value when discussing a comparison, highlighting a table cell, building a progression or trend, and revealing a dense graph, gel or image in smaller pieces. ^{77, 79, 29} Patient-flow diagrams can be discussed in parts and then shown as a whole. ^{79, 78} Animation needs checking so that a highlight does not appear before its text. ⁷⁶

Elaborate transitions can distract from the story, and equipment compatibility or congress instructions may rule them out; a simple fade is one more restrained option. ^{35, 80, 10, 29}

Review and professional finish

A minimum set of slide-design guidelines recommends: ^{19, 81}

Element	Basic guideline
Arrangement	One point per slide
Font colour	Black or dark text on white
Colour	Avoid overuse
Testing size and colour	Project in an appropriately sized and lit room; check readability and colours
Images	Keep them simple and relevant
Software	Allow enough time to design and refine ideas
Hardware	Plan for problems
Audiovisual principles	Do not duplicate the speaker's words on the slide
Coherence	Treat each slide as a whole within the whole programme

¹⁹

Images should be tested with others and removed if they do not work; visual thinking can take longer than writing words. ¹⁹ Design requires understanding the information, judging its parts' relative importance and translating it into visuals that support the presentation. ⁸² A lack of training in slide design and audiovisual perception can perpetuate ineffective practices. ⁸²

Abbreviations should be defined on the slide where they first appear, using the full term followed by the abbreviation in brackets; an abbreviation used only once or twice may be better avoided. ^{72, 83, 84} For example, DNA might mean “did not attend” rather than the nucleic acid. ⁸³

A delay before rereading helps reveal errors. ⁸⁵ The finishing check covers: ⁸⁵

• Alignment.
• Typography.
• Bullets and spacing.
• Colours and contrast.
• Spelling.
• Defined abbreviations.

⁸⁵

One critique of a superficially acceptable slide found unnecessary colours, mixed serif and sans serif faces, yellow and white text together, inconsistent bolding and title capitalisation, poor alignment, differently coloured symbols, inconsistent spacing around arithmetic operators, an x-axis label split over two lines, a missing closing bracket and unnecessary bar borders. ^{86, 87, 62}