KPI Notation

Prefixes: Units on Variable Type

Usually, the units are clear from context. If not we can use the following abbreviations for clarity. But we can also prefix $\%$ and $\Delta$ :

Meaning	Abbreviation	Example
Number of	$\#$	$\#{Pageviews}$
Money amount	$\$$	$\${R}$
Percent	$\%$	$\%ROE$
Delta (difference over time)	$\Delta$	$\Delta R$
Average	$\varnothing$	$\varnothing INV$

Suffixes: Time Windows

Time Windows for Flow Variables

For Flow Variables, a time refers to a time window, and not to a point in time as for Stock Variables.
Whether the above subscript refers to a point in time or to a window is usually clear from the context. However, sometimes we want to clarify the time window of a flow variable. We do this with a suffixed time window designation:

Time Window	Notation	Example
per year (per annum)	$\text{p.a.}$	$\#\,New Joiners\,\text{p.a.}$
per month	$\text{p.M.}$	$R\,\text{p.M.}$
per week	$\text{p.w.}$	$\#\,{Storypoints}\,\text{p.w.}$
per day	$\text{p.d.}$	$\#\,{Pageviews}\,\text{p.d.}$
per hour	$\text{p.h.}$	$\#\, {Pieces}\,\text{p.h.}$

Superscripts: Variable Specification

If a variable needs a specification or a detailed definition, we use a superscript:

$C^{delivery}$: Delivery Costs
$M^{net}$: Net Margin
$P^{cost}$: Cost Price

Exceptions to these rules are definitions that are commonly used, especially accounting terms such as e.g.

$EBIT$ Earnings before Interest and Taxes (and not $E^{BIT}$)
$COS$ for Cost of Sales (not $C^{OS}$)

Subscripts: Indices

With a subscript index, we clarify the Dimension of a variable. Indices are always a single, lower case letter.

For example:

$C^{Production}_{p}$: Production cost of product $p$.
$M_{c}$: Margin of the channel $c$.

If a variable can be indexed by multiple dimensions, we separate by comma:

$M_{p,c}$: Margin of product $p$ on channel $c$.

The following indices are commonly used:

Index	Variable	Example
p	product	$P_p$: Price $P$ of product $p$
c	channel	$M_{c}$
o	order	$P^{cost}_{o}$: The cost price of order $o$
l	order line	$M_{l}$: Margin of order line $l$
d	division	$FTE_d$: Headcount in division $d$
k	customer	$AR_k$: unpaid invoices for customer $k$
s	supplier	$P_{l,p}$: price of supplier $l$ for product $p$
t	time	$R_t$: revenues in period $t$

Meaning	Abbreviation	Example
Number of	\(\#\)	\(\#{Pageviews}\)
Money amount	\(\$\)	\(\${R}\)
Percent	\(\%\)	\(\%ROE\)
Delta (difference over time)	\(\Delta\)	\(\Delta R\)
Average	\(\varnothing\)	\(\varnothing INV\)

Time Window	Notation	Example
per year (per annum)	\(\text{p.a.}\)	\(\#\,New Joiners\,\text{p.a.}\)
per month	\(\text{p.M.}\)	\(R\,\text{p.M.}\)
per week	\(\text{p.w.}\)	\(\#\,{Storypoints}\,\text{p.w.}\)
per day	\(\text{p.d.}\)	\(\#\,{Pageviews}\,\text{p.d.}\)
per hour	\(\text{p.h.}\)	\(\#\, {Pieces}\,\text{p.h.}\)

Index	Variable	Example
p	product	\(P_p\): Price \(P\) of product \(p\)
c	channel	\(M_{c}\)
o	order	\(P^{cost}_{o}\): The cost price of order \(o\)
l	order line	\(M_{l}\): Margin of order line \(l\)
d	division	\(FTE_d\): Headcount in division \(d\)
k	customer	\(AR_k\): unpaid invoices for customer \(k\)
s	supplier	\(P_{l,p}\): price of supplier \(l\) for product \(p\)
t	time	\(R_t\): revenues in period \(t\)