Data Visualisation

Use. Amounts across a handful of categories, against a named baseline, peer, prior period or target

Never. Bars with no comparison named, or a scale cut short without saying so

Use. Two values for each category, such as before and after, or actual against target

Never. More than two points on one row

Use. The change between exactly two moments, for several items

Never. Three or more moments. Use a line or a bump

Use. A value at every crossing of two lists, read as a pattern

Never. Exact reading of single values. Use a table

Use. One value per category against a marked reference, such as a cohort median

Never. Dots with no reference to read them against

Use. Actual against target for several measures, with the shortfall visible

Never. Targets the piece does not state

Use. Two groups back to back across the same categories, such as two answers by age. By age and sex it is a population pyramid

Never. Groups that do not share the categories

Use. Many categories ranked, where bars would be a wall of ink

Never. A scale that does not start at zero

Use. One figure that carries the point, with what it is compared against, such as 37 of 100

Never. A number with no comparison, period or source

Use. Exact values the reader will look up, with bars or shading in the cells where a pattern matters

Never. A table where the reader needs the pattern, not the values. Draw the chart

Use. A continuous trend over regular time

Never. Uneven gaps drawn as if they were even

Use. Rank order moving across several snapshots

Never. Values, when the size of the gap matters

Use. The shape of a distribution, one row per period or group

Never. Fewer than four rows

Use. A starting total carried to an ending total by the gains and losses between

Never. Contributions that do not add up to the change

Use. Dated events in order, with the gaps between them meaningful

Never. Undated steps. Use a process

Use. Pieces of work across dates, with overlaps and dependencies

Never. A plan nobody holds to

Use. One total over time, where the volume is the point

Never. Several overlapping areas. Use small multiples

Use. Open, high, low and close for each period, for a price

Never. Any measure that is not traded

Use. Two measures over the same periods, one as columns and one as a line, such as revenue and margin

Never. Two scales set so the measures appear to move together

Use. One series against the pack, the rest muted and unlabelled

Never. Every series in full strength

Use. How two measures moved together over time, the path joined in order

Never. A path the reader cannot follow without arrows

Use. Where each item started and ended on one or two measures

Never. Arrows that cross so often they hide the movement

Use. Items against a line where the two measures are equal, so the one off the line shows

Never. A parity line with no meaning in the piece

Use. A central estimate with the range it could plausibly fall in

Never. A band whose level of confidence is not stated

Use. A forecast whose range widens the further it reaches, after the last observed value

Never. A forecast drawn as a single line

Use. A measure over time against bands that say what is good, normal or poor

Never. Bands the piece does not define

Use. The low and high for each group, side by side

Never. Ranges with different meanings on one chart

Use. A point and its interval for each group, read against a reference

Never. An interval whose level of confidence is not stated

Use. The full shape of a distribution for a few groups

Never. Readers who need only the median. Use a box plot or a dot plot

Use. Shares that add to a whole, or views split either side of neutral

Never. Eight or more segments

Use. Part of a whole where the relative sizes are the point

Never. Parts too small to label

Use. A whole split two ways at once, such as market by region and by segment

Never. A split the reader cannot name both ways

Use. Drop-off from one stage to the next

Never. Stages that are not a subset of the one before

Use. One series across categories that repeat in a cycle, such as months

Never. Categories with no cycle

Use. Two or three shares of one whole, where one share is the point

Never. More than three slices, or two pies compared

Use. The same as a pie, with the total in the middle

Never. More than three segments, or segments the reader must compare

Use. A whole broken down two levels deep, as rings

Never. Three levels or more

Use. How the parts of a total moved over time

Never. More than four parts, or parts the reader must compare one by one

Use. How the mix ebbed and flowed, when the shape matters more than the values

Never. Exact reading of any part

Use. Net gains and losses over time either side of zero

Never. Gains and losses that are not of the same thing

Use. Items ranked by size, with a running total showing how few make up most of the whole

Never. Items that are not parts of one total

Use. Whether two measures move together

Never. A line of fit drawn with no reason given in the piece

Use. A scatter with a third measure that matters, as size

Never. Size the reader is asked to compare exactly

Use. Every item along one measure, one dot each

Never. More dots than the size can hold apart

Use. A point and its interval for each group, read against a reference

Never. An interval whose level of confidence is not stated

Use. How one measure is spread, in bins of equal width

Never. Bins of unequal width without saying so

Use. The same chart repeated for each group on one shared scale

Never. Scales that change from panel to panel

Use. A trend in the space of a word

Never. A sparkline the reader must read values from

Use. Daily values laid out as weeks, so the rhythm of the week shows

Never. Data that is not daily

Use. Several items compared on many measures at once, one line each

Never. More items than the lines can keep apart

Use. A share of a group shown as a hundred people or units, some filled

Never. Shares that do not count people or units

Use. How unequally something is shared, against a line of perfect equality

Never. A curve with no equality line to read it against

Use. An amount splitting and joining across stages, with width as the amount

Never. Widths that do not add up across a stage

Use. Steps in order, with what passes between them

Never. Branches. Use a flowchart

Use. A decision with branches, each branch labelled

Never. A branch that ends nowhere

Use. Steps owned by several people or teams, with each handoff shown

Never. One owner. Use a process

Use. Messages between actors, in time order down the page

Never. A step with no sender or receiver

Use. One thing moving through states, with what moves it, including waits, retries and endings

Never. States the thing cannot actually be in

Use. A cycle where the last step feeds the first, and something builds up each time round

Never. A list of steps that does not return. Use a process

Use. Flows between a handful of groups in both directions, around a circle

Never. More groups than the circle can label

Use. Parent and children, one parent each

Never. A child with two parents. Use a dependency graph

Use. Who owns, reports to or escalates to whom, for people, teams or agents

Never. Names the person has not cleared to show

Use. Hierarchy by containment: what sits inside what

Never. More than three levels deep

Use. Levels stacked by abstraction, each resting on the one below

Never. Layers that do not depend on each other

Use. A ranked hierarchy, widest at the base

Never. A ranking the piece does not argue

Use. Overlap between two or three sets, with the overlap named

Never. Four or more sets

Use. The parts of one object pulled apart along one line, in assembly order

Never. Parts that do not assemble into the whole

Use. One floor or site seen from above at an angle: rooms, zones, phases

Never. Places the piece does not describe

Use. Who or what is connected to whom, when the links are the point

Never. Every link drawn when only a few matter

Use. Items placed on two axes, each axis named for what high and low mean

Never. Axes that are not independent

Use. A chain of needs set against how settled each part is, to show what to build, buy or leave

Never. A chain with no user at the top

Use. The causes of one observed effect, grouped by kind

Never. Causes the piece does not name

Use. What depends on what, with shared parts and cycles a tree cannot show

Never. Every link, when only the critical path matters

Use. Choices and chances branching to outcomes, each with its value

Never. Probabilities or payoffs the piece does not state

Use. What each of two players gets for each pair of moves

Never. More than two players, or moves the piece does not name

Use. Two curves whose crossing or peak marks the best choice

Never. An optimum the piece does not argue

Use. Moves made in turn by two players, each branch ending in what both get

Never. Moves or payoffs the piece does not name

Use. A question broken into parts that do not overlap and together cover it

Never. Branches that overlap or leave a gap

Use. The pressures on a market's profits: rivals, new entrants, substitutes, buyers and suppliers

Never. Forces drawn without saying which one bites

Use. The steps a business takes to make and deliver what it sells, and where it earns its margin

Never. Steps the business does not own, drawn as its own

Use. Competitors' offers scored on the same factors, one line each

Never. Factors or scores the reader cannot check

Use. Adoption or performance that starts slow, climbs, then levels off

Never. A curve fitted to too few points

Use. Today's business, the next one and the one after, set against time and value

Never. Horizons with no investment named in each

Use. Business units on two axes such as market growth and share, sized by revenue

Never. Cut-off lines the piece does not state

Use. A rate per area, shaded by region

Never. Raw totals, which only show where people live

Use. Amounts at places, sized by value

Never. Symbols that overlap so much they hide each other

Use. Movement between places, with width as the amount

Never. Every route drawn when a few carry the argument

Use. The path taken, with its stops in order

Never. A route the piece does not describe

Use. Every region as an equal tile, so small regions count

Never. Readers who need the real shapes to find a region

Use. Regions resized by a value, such as population

Never. A value readers cannot recover from the distortion

Use. How a count spreads across a place, one dot per so many

Never. Dots read as exact locations

Use. What a person does across the stages of an experience, and how it feels

Never. Feelings the piece does not report

Use. What the customer sees against what the service does out of sight, with the line between them

Never. Steps nobody owns

Use. A narrative backbone, sliced into releases, with the cut line drawn

Never. A backlog with no order

Use. Work in progress by state, with limits and blocked items

Never. A board that is not kept current

Use. Parts of a system and how they connect, in one snapshot, with boundaries of trust or ownership

Never. Every service, when three carry the argument

Use. A change in structure, drawn twice on the same layout, with a list of what changed

Never. A change in settings only. Use a table

Use. A landscape as it stands today, by phase or department

Never. Today's picture labelled as the target

Use. Who does what to the data at each step

Never. Steps without an owner

Use. Sources, a core and the people or systems that use it

Never. Every source, when the argument needs the shape

Use. Storage in levels of quality, with who may reach each

Never. Levels the system does not enforce

Use. Which role may do what to which part

Never. Permissions nobody has checked

Use. Where software runs: zones, hosts, copies, ports

Never. Detail a reader of the piece will not use

Use. Things, their fields and how they relate

Never. Every field, when the relation is the point

Use. Physical tables, types, keys and indexes

Never. A reader who is not building on it

Use. Classes, what they do, and how they inherit or contain

Never. A different kind of software diagram drawn in its notation

Use. Three to five scores on a common scale, for one to three entities

Never. Ranking. Use a bar