On percantages … and a bit more - PowerPoint Presentation

1. On percantages…and a bit more AL, nov. 2013

2. Font style for %: bold, italics, regular?Definitively NOT boldBold should be strictly reserved for text emphasis (highlighting in text)there is no reason why % should be emphasized vs. absolute values (they are not more important) – they should only be differentiatedSo only write %XY in bold if this is a text highlight, not because it is a percentage!% in italics is OKText in italics has lower readability, but this is more important for longer texts (does not apply to our case so much)By consistently using italics for %, we increase the distinction between absolute values and percentages. I think it is a good idea which has more positive than negative effects.Can be universally applied in tables and in chartsStraightforward implementation in any tool – no problems hereI suggest a strict rule: % always in italics (tables, charts, highlights…)

3. Rules on writting or omitting the % sign?„Reducing Redundancy“ rule: % sign can be omitted from numbers in a series, if it is written in front (top or left) of the series values (in the series name).Benefit: higher data-ink ratio, less clutter, higher readability of numbersDrawback: higher threshold of understanding/learning the sign system (steeper learning curve)So if we write % behind numbers, everybody will immediately understand the values,If we do not write it, „new“ users will find it a little confusing at the beggining…TablesI think here the rule must be applied:Write the % sign in the column header (Question: in front of series name or after?)Write the values without the % sign (but in italics!)I think this is still IBCS standard, right?ChartsTricky… maybe we allow both options?Personally I prefer no % sign in numbers, only in series legend (e.g. %AC-PY). But I have seen in consulting work that customers generally prefer having the % sign on all numbers…Zebra BI will allow both options.Highlights% sign must always be with the number?The „Reducing Redundancy“ rule does not apply here, because there is no redundancy!If % in key message is written in brackets e.g. (+15%), then we can use the brackets also in highlights (as I proposed for BARC examples) – has to be defined as a rule (for better message – highlight consistency)And also here: italics

4. From:To:MeaningVisual variable1From (Basis)(Axis) line pattern2ToMarker pattern3SizeLength of deviation line4Good/BadRed/green colorDeviation = To - FromVariance %: shapes are now defined, only some minor problems left

5. Marker shapes, colors and sizes in Variance %In current IBCS definition we are using 4 different visual variables to code Scenarios – a simple (but important…) category dimension with only 4 elements:1. Pattern2. Shape3. Size4. Color LightnessMy comments/suggestions:Using 4 visual variables is unnacessary, too complicated and produces problems in implementation and interpretation. Applying different sizes is wrong! We should cancel the 50% size rule, because it produces a lie factor + cannot be consistantly applied to all charts. On top of that, size is also used for (1) time periods (YQM) and (2) Volume/Value (Volume width = X% Value width?)Using shapes for scenarios is OK in % variance charts („Pins“), but creates at least these problems: (1) is redundant to pattern and causes inconsistency, because scenario shapes can only be aplied to markers (and not to lines, columns, areas, circles…) (2) selected shapes are not intuitive enough (3) we „loose“ a very important visual variable (shape), which could be used for other meaning - in my opinion especially measures (KPI) ↓I propose using ONLY pattern for scenarios, nothing else… no shapes, no sizes

6. It this Value or Volume? Which measure is it: Revenue, Costs, Headcount, Units sold…?Is it % variance of a measure?Is it variance of a Structure %?Is it variance of a Ratio %? And which ratio: Gross Margin%, %EBITDA, …?Is it Percentage points?Now we can use shape to differentiate between different measures and percenatage typesThis part of notation is brilliant and I think it is no. 1 feature of IBCS

7. Percentage typesStructure % („Portfolio Share“) = Part / Whole * 100Volume structure % = Part (Volume) / Whole (Volume) * 100Value structure % = Part (Value) / Whole (Value) * 100Ratio % = Value 1 / Value 2 * 100Volume ratio % = Volume 1 / Volume 2 * 100Value ratio % = Value 1 / Value 2 * 100BTW: Can we find a better term than Ratio for this? Ratio seems too general…Variance % = (Actual* - Baseline) / Baseline * 100Actual* here means any scenario that is compared to Baseline (usually AC, but also FC, PL…) – do we have a word for this?Notation: I would write %AC-PL instead of ΔPL% and %FC-PY instead of ΔPY%(this is too complicated and I think it is better to separate text elements from visuals + it is hard to implement in software tools – not very practical)Percentage points (pp)Difference between two percentages. Can be a variance (+/-, R/G), but not necessarily…Notation: Not 100% sure, perhaps better pp than %p (it is standard and better differentiates from %, although I like the idea of still having % sign). Also possible: %. (percent + dot/point)Division of an element (Part) by Whole within a category dimension of the same measure (either a volume or a value)Division of two different measures of the same type (either a volume or a value)Division of a variance by base value within the scenario dimension of the same measure (either a volume or a value)Difference between two percents (of any type: variance, structure, ratio!)

8. Ideas on differentiating percentage shapes…

9. These 4 types of percentages are very different things,but they are all about division (and two of them also about subtraction)So how does (A) division and (B) subtraction of shapes look like? Perhaps like this?Net RevenueCOGSGross ProfitGrossProfitFixedCostsProfit/Loss③ = ① - ② ①②③(A)(B)①②③ = ② / ①

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11. „Mushroom“ Chart„Hammer“ Chart„Tulip“ ChartAB = A/2ABBC = B/2% Structure always scaled?

12. Ratio %Structure %Variance %Percentage points„points“ = dots ;)