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# Usage
```
 ,' ,-_-. '.
((_/)o o(\_))
 `-'(. .)`-'
     \_/

Copyright (C)  2019  Marco Bresciani.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
copy of the license is included in the section entitled "GNU Free
Documentation License".
```
## Usage Hints
Since this is not (yet?) a fully-featured Kanban tool with a ton of
metrics, but a simple spreadsheet aiming to help in personal (and
continuous) improvement, there is no need to have a detailed scientific
description of all charts and metrics (see the reference books, for
those). In this section you can find some human-friendly and empirical
hints to help you read the charts and continuously improve your work
flow.
* Limit WIP, to avoid spreading effort on too many work items. The
  *Effort Run Chart* shows you how much percentage of your working time
  you're giving, on average, to each ongoing work item.
* The [CFD](#CFD) chart should show almost parallel lines, if some
  levels increase or decrease too much with respect to other levels
  (diverge), there might be a bottleneck.  
* Try to keep throughput (or, even better, the delivery rate) as much
  steady as possible, and always aim to increase it in order to increase
  your completion speed. This will help your predictability.
* The idea behind the [Distribution](#Distribution) charts is to make
  the curved shape as thin and higher as possible, so reducing the long
  tail given by higher lead times.
* Always analyze root causes for special work items, that is: check why
  completed work items have lead times higher than overall 95th (or
  maybe 85th) percentile values. There might be room for improvement to
  avoid further work items with long lead times.
* If work items are blocked too many times or for too longer time,
  always check the root causes and improve on that side: removing
  blockers helps you moving your work items faster through the flow. 

## Spreadsheet composition
The whole spreasheet, in LibreOffice Calc format, contains these sheets:
* [Notes](#Notes)
* [WorkItems](#WorkItems)
* [CFD](#CFD)
* [Lead Time](#Lead-Time)
* [Little's Law](#Little's-Law)
* [Metrics](#Metrics)
* [Distribution](#Distribution)
* [Data](#Data)

and it can be modified and used following the [GNU General Public
License (GNU GPL)](https://www.gnu.org/licenses/gpl.html).

For daily normal use, [WorkItems](#WorkItems) should be the only sheet
you need to work on, while all other sheets are there to let you read,
report and visualize metrics. There are no hidden sheets nor
password-protected cells. The whole spreadsheet is completely available
for you, following the license terms.

Please note that [WorkItems](#WorkItems) sheet already contains some
data. Those are sample data to show you how to use and write them. Feel
free to remove (or overwrite) them.

## Notes
The [Notes](#Notes) sheet is just a sort of cover page for the whole
spreadsheet with licensing notes and the version number of the release,
for reference.

## WorkItems
For daily usage purposes, [WorkItems](#WorkItems) is the only sheet you
need to work on and modify, by adding your own work items tracking.

The whole [WorkItems](#WorkItems) sheet is compatible with [Actionable
Agile™ Analytics](https://www.actionableagile.com/) tool (see [Format
for Data File](https://www.actionableagile.com/format-data-file/)):
simply export [WorkItems](#WorkItems) sheet as CSV (select comma
(**,**) as cell separator and quotes (**"**) for fields) and then import
it in the tool.

As described in the [Format for Data
File](https://www.actionableagile.com/format-data-file/) page, The first
row contains the column names for each of the data fields.
* The first column is an item **ID** field.
* The second column is optional, and it's the **Link** to the item
  location in your online Kanban/Agile/PM tool, if any. If not used, it
  can be hidden.
* The third column is optional (but I strongly suggest to use it), and
  it's the item **Name** (or title or description) field.

The next set of contiguous columns are the sequential steps of the
workflow. Currently, due to the basic needs of Personal Kanban concepts,
they have been set to **Backlog** (optional, as described above, but I
strongly suggest to use it), **Next**, **In-progress** and **Done**.
The contents of these columns are the date the item entered each
workflow step. For standardization purposes, the dates are displayed in
ISO8601 date format (year, four digits; `-`; month, two digits; `-`;
day, two digits: `yyyy-mm-dd`) but can be entered in your local format
(e.g.: `dd/mm/yyyy` or whatever), as configured in LibreOffice Calc.

The **Backlog** column contains the date when the work item appears,
when you had a new idea, a new task appears, or anyway when something
potentially doable appears in your work system.

The **Next** column represents the date when the work is definitely
committed by the person/entity that asked for it or when you decide that
the work has to be done. For example: you may have an idea for a very
good book, but this does not mean that you actually have to write it.
Unless you firmly decide to write it. This is  called *Commitment
point*, The point in a kanban system at which the commitment is made to
deliver a work item. Before this point, work done supports the decision
whether or not to deliver the item. After this point, it has been
confirmed that the customer wants and will take delivery of the item,
and that the service will deliver it.

The **In-progress** column contains the date when you have started
working on the work item activity.

The **Done** column contains the date when the result of the work item
activity has been delivered/provided to the person/entity that asked for
it.

These above are the mandatory columns for metrics. There are also
optional columns that may help identifying work items and their
information:

* **CoS** is the Class of Service of the work item and it should help
  differentiate items based on their Cost of Delay. Each class of
  service has a specific execution policy that the team agrees to
  follow. Those following are the basic standard classes of service
  defined in [Kanban](https://leankanban.com/shop/kanban-book/) book and
  predefined as available in this sheet. If you need other classes of
  service, feel free to modify the sheet according to the license above.
  Traditional Classes of Service can be described as:

    * *Expedite*, has an unacceptable cost of delay and therefore
      requires immediate attention. It can be pulled into development,
      even in violation of current WIP limits (even if it shouldn't
      be…). Typically, there can be only one expedite item in the system
      at a time, and teams may set a policy to swarm on that item to
      make sure it moves through the system rapidly.
    * *Fixed date*, describes work items that must be delivered on or
      before a specific date. Typically, the cost of delay of these
      items is nonlinear and is highly sensitive to small changes in the
      delivery date; these must be actively managed to mitigate the
      schedule risk. Therefore, these items are pulled into development
      when necessary to be finished on time. Some items may require
      additional analysis to refine the expected lead time. Some need to
      be reclassified as expedite if the team falls behind.
    * *Standard*, represents the baseline class of service, applicable
      to work items that are neither expedited nor fixed date. Most
      backlog items should fall into this category. The cost of delay is
      linear for standard items, meaning that value cannot be achieved
      until delivery occurs, but there's no fixed-date requirement.
    * *Intangible* is used for work that goes through the system that
      doesn't directly deliver value to the customer. This is work that
      needs to be done - but for which it is hard to show a return on
      investment. It is a good idea to have some Intangible work going
      through the system. It is better to set this aside when an
      Expedite comes through then work with an associated due date or
      cycle time expectation.

* **WIT** is the type of the work item (Work Item Type) and it should
  help categorize items based on your ideas, needs and concepts. Each
  work item type is specific for the person or team or group that define
  it and it has a specific meaning. Some examples can be: "work",
  "home", "children", "taxes" or whatever category or main argument you
  may want to use to aggregate items information and types. There are no
  pre-defined WITs in this sheet.

* **Deadline** is usually used for Fixed Date CoS only and it represents
  the date before which the item shall be completed. The column value is
  anyway optional, even for Fixed Date CoS. The content is automatically
  formatted to ISO8601 standard as described above and conditionally
  formatted with the following rules:
   * today, red background cell;
   * this week, orange background cell;
   * this month, yellow background cell;
   * next month, green background cell;
   * expired completed work item, red text.

* **Blocked Days** represents the total number of days when the work
  item was blocked due to external dependencies or events or any reason
  for which the item itself was not available to work on. In order to be
  properly evaluated, it shall be computed as the difference between two
  dates, plus one. That is: if a work item has been blocked today only,
  the Blocked Days column shall count 1 while if the work item has been
  blocked yesterday and today, the column shall count 2, etc. It is
  obviously possible to add multiple blockers, even through formulas,
  by simply adding the intervals and rembering to add 1 for each:
  `=(date(2019,8,15)-date(2019,8,12)+1)+(today(2019,3,5)-date(2019,3,3)+1)`
  that represents a blocker from 2019-08-12 to 2019-08-15 (4 days) and
  another blocker from 2019-03-03 to 2019-03-05 (3 days), for a total of
  7 blocked days.

* **Deleted** is the column that contains the date when a work item has
  been considered discarded (while in Backlog) or the work is aborted
  (while in Next or In-progress) and no more bringing value to the flow.

  > *While bug [#109947](https://savannah.nongnu.org/support/?109947) is
    open*, when a work item has to be discarded or is aborted, *you*
    have to write such cancellation date in all remaining columns cells
    and also write the same date in the **Deleted** column. With this,
    the work item will be properly identified as deleted.

* The **Labels** column may contain a set of strings and text
  identifiers (labels) that can be used to further filter, categorize or
  tag the work items in order to better identify and collect their
  metrics. As shown in the example data of [Actionable Agile™
  Analytics](https://www.actionableagile.com/) tool, a single label can
  be written as simply as `A` while possible multiple labels can be
  represented as `[A|D|Y]`. The tool will take care of using them for
  filtering purposes. This spreadsheet has currently no use for this
  column, and it can be hidden.

All those columns above are properly managed by the [Actionable Agile™
Analytics](https://www.actionableagile.com/) tool as attributes that can
be filtered and grouped. Filtering by **CoS** or **WIT** or other
columns is not yet supported in this spreadsheet.

## CFD
The [CFD](#CFD) dashboard sheet has the name tab highlighted in green
colour to show that it does not contain nor compute data but represents
them in charts.

If not otherwise specified, charts in this dashboard contain or manage
data enough to run the board for ten average Gregorian years (3652
days). 

It contains some major metrics charts such as:
* *Cumulative Flow Diagram* (CFD) that shows:
  * a gray line showing the cumulative total number of work items that
  were created (**Backlog**);
  * a red line showing the cumulative total number of work items that
  has been commited (moved to **Next** column) for completion;
  * a yellow line showing the cumulative total number of work items that
  has been worked on (moved to **In-progress** column);
  * a green line showing the cumulative total number of work items that
  has been completed, or cancelled after commit (moved to **Done**
  column). There is no distiction between actually completed work items
  and work items that have been cancelled after the commitment point.

  The horizontal axis is a timeline and each work item is marked on the
  date of status update. The vertical axis represents the cumulative
  total number of work items for such status on the reference date. This
  chart is a representation of the ongoing status of the service flow.

  For a detailed description of the behaviours and issues you can find
  with a Cumulative Flow Diagram, take a look at this relevant and
  interesting article by Pawel Brodzinski on his blog: [Cumulative
  Flow Diagram](http://brodzinski.com/2013/07/cumulative-flow-diagram.html).
* The *Daily Run Chart*, is the run chart for the daily values of
  **Backlog** (gray, number of work items waiting), **DR** or Delivery
  Rate (light green, number of daily completed work items),
  **Throughput** (green, number of daily done (completed + discarded)
  work items) and **WIP** (orange, number of ongoing work items).
* The *Backlog Age Distribution* is the distribution chart representing
  the amount of time work items wait in Backlog before being committed.
  The chart includes data from all work items that has been created,
  regardless they are still in *Backlog*, they are in progress or
  already done.
* The *CoS Ratio* chart shows the Classes of Services ratio with respect
  to the total number of work items. It uses the four standard Classes
  of Services, and the colours are those defined as examples in
  [Kanban](https://leankanban.com/shop/kanban-book/) book. 
* The *Flow Efficiency* is the run chart for Flow Efficiency with its
  moving average from the **FE** and **mFE** columns in
  [Metrics](#Metrics) sheet.

## Lead Time
The [Lead Time](#Lead%20Time) dashboard sheet has the name tab
highlighted in green colour to show that it does not contain nor compute
data but represents them in charts.

If not otherwise specified, charts contain or manage data enough to run
the board for ten average Gregorian years (3652 days). 

It contains some charts related to Lead Time metric such as:
* the *Lead Times Scatterplot* chart of completed and ongoing
work items, starting from the earliest to the current date. The scatter
plot shows:
  * a blue dot for each "Done" work item with the value of its
    corresponding **LT** (Lead Time);
  * a red upward pointing triangle for each work item still in progress,
    with the value of its current **Age** (number of days since it
    entered **Next** state);
  * a red dotted line representing the moving average of the **95th
    percentile** of the **LT** values;
  * an orange dotted line representing the moving average of the **85th
    percentile** of the **LT** values;
  * a yellow dotted line representing the moving average of the **70th
    percentile** of the **LT** values;
  * a green dotted line representing the moving average of the **50th
    percentile** of the **LT** values;
  * a blue dotted line representing the moving average of the **LT**
    values themselves (**mLT**).

  The horizontal axis is a timeline and each work item is marked on the
  completion (**Done**) date while in progress items are marked on
  commitment (**Next**) date. The vertical axis represents the number of
  days: lead time of completed work items goes from the committment
  point (when the work item enters the **Next** column) to the **Done**
  status (either completion or discard); age of ongoing work items goes
  from the committment point (**Next**) to current date.

  This chart is a representation of how long (**LT**) it takes to get
  things done for individual work items on your kanban board and the
  trends the **LT** has.

  Possible uses for scatterplots are:
  * visualize clearly the lead times of the work items, possibly
    filtering them according to CoS or WIT;
  * compare different WITs lead times;
  * forecast the lead time of future work items.

  For a detailed description of the behaviours and ways to read a lead
  time scatterplot, take a look at this article by
  [Kanbanize](https://kanbanize.com/): [Using Scatter Plot to Measure
  and Forecast Cycle
  Time](https://kanbanize.com/kanban-resources/kanban-analytics/cycle-time-scatter-plot/)
  with further details on [Meet the Cycle Time Scatterplot from Premium
  Analytics](https://kanbanize.com/blog/premium-cycle-time-scatterplot/).
* The *Lead Times Distribution* is the chart that represents the
  bin-constrained frequencies of Lead Times for all done work items. It
  plots the frequency of lead times, split in a set of 42 bins from the
  lowest to the highest with an blue dotted line overlay of the
  estimated Weibull distribution for such frequencies, if any. The
  values that are involved are **F(LT)** and **Weibull(LT)** from
  [Distribution](#Distribution) sheet.
* The *Throughputs Distribution* is the chart that represents the
  bin-constrained frequencies of Throughput values for all days. It
  plots the frequency of throughputs, split in a set of 42 bins from the
  lowest to the highest with an green dotted line overlay of the
  estimated Weibull distribution for such frequencies, if any. The
  values that are involved are **F(Throughput)** and
  **Weibull(Throughput)** from [Distribution](#Distribution) sheet.
* the *Lead Times Detail* charts work items Lead Times splitting them
  according to the time spent in each workflow status.

  For example: if a completed work item has spent 2 days in **Backlog**,
  3 days in **Next** and 12 days in **In-progress**, then the bar for
  such work item will be 17 days long, split in three differently
  coloured sections: a gray part, 2 days long, for **Backlog**; a red
  part, 3 days long, for **Next** and a yellow part, 12 days long, for
  **In-progress**. Keeping the same colour-conventions as in the
  *Cumulative Flow Diagram*, this chart shows:
  * a gray vertical bar showing the total number of days a completed
    work item has spent in the **Backlog** column;
  * a stacked red vertical bart showing the total number of days a
    completed work item has spent in the **Next** column;
  * a stacked yellow vertical bar showing the total number of days a
    completed work item has spent in the **In-progress** column.
 
  These are actual (calendar) days: if a work item has been moved from
  **Backlog** to **Done** in the same day, all column will be 0 (zero),
  but the corresponding Lead Time for such work item will be 1 (one)
  day.

  Since this is a bar chart, it cannot be spread to include 3652 days
  like, say, the *Lead Times Scatterplot* chart because it does not
  automatically scale to skip empty values. So, while categories include
  the whole ten (average Gregorian) years set, the values of
  **Backlog**, **Next** and **In-progress** columns have been
  limited to 42 rows. Feel free to increase it, as soon as you have more
  than 42 work items.
* *WIP Run Chart*, is the chart that shows the ongoing daily **WIP**
    values together with its moving average (**mWIP**) and the weekly
    moving average (**mWIP(7)**), computed only on the latest seven days
    of actual data).
* *Throughput Run Chart*, is the chart that shows the ongoing daily
  **Throughput** values together with its moving average (**mThr**) and
  the weekly moving average (**mThr(7)**), computed only on the latest
  seven days of actual data). Additionally, it shows the standard
  deviation of the Throughput values (**σThr**) that is used to quantify
  the amount of variation or dispersion of those values. A low standard
  deviation indicates that the data points tend to be close to the mean
  (also called the expected value) of the set, while a high standard
  deviation indicates that the data points are spread out over a wider
  range of values.

## Little's Law
The [Little's Law](#Little's-Law) dashboard sheet has the name tab
highlighted in green colour to show that it does not contain nor compute
data but represents them in charts.

If not otherwise specified, charts in this dashboard contain or manage
data enough to run the board for ten average Gregorian years (3652
days). 

The dashboard contains some charts related to Little's Law and other
useful metrics such as:
* The *Little's Law*, is the *LT = WIP / Thr* chart that represents the
  three terms of Little's Law. Running average of WIP (**mWIP**,
  orange), computed on actual data; running average of Throughput
  (**mThr**, green), computed on actual data; running average of Lead
  Time (**mLT**, blue), computed as ratio between those two values
  above;
* *I/O speed*, is the chart that represents the running average speed of
  incoming (**mArrival**) and outgoing (**mThr**) work items, in terms
  of average number of work items per day. There is also the running
  average of delivery rate (**mDR**) considering only completed
  work items, without discarded/deleted ones. The throughput is
  represented on the secondary (right-side) Y axis.
* *Blockers*, is the chart that represents the running average
  **Impact** blockers may have in a work item, that is the average
  number of blockers (day) that may happen during a work item lifetime,
  the average **Likelihood** (probability) that a blocker might happen
  during a work item life (on secondary, right-side, Y axis) and the
  average **Risk** that a blocker may represent, as product between the
  two previous values.
* *Little's Law (7 days)*, is the *LT = WIP / Thr* chart that represents
  the three terms of Little's Law. Running average of WIP (**mWIP(7)**,
  orange), computed only on the latest seven days of actual data;
  running average of Throughput (**mThr(7)**, green), computed only on
  the latest seven days of actual data; running average of Lead Time
  (**mLT(7)**, blue), computed as ratio between those two values. The
  throughput is represented on the secondary (right-side) Y axis;
* The *Approximate Average Lead Time*, shows the **mLT** value, together
  with the trend of the approximate average lead time (**AALT**), as
  shown by the CFD chart. The approximate average lead time is described
  in chapter 9 of the [Actionable Agile Metrics for
  Predictability](https://leanpub.com/actionableagilemetrics) book (as
  Approximate Average Cycle Time) and a practical example is show in
  [Actionable Agile Metrics for Predictability by Daniel S. Vacanti,
  Re-read Saturday Week 10: Flow
  Debt](https://tcagley.wordpress.com/2017/12/23/actionable-agile-metrics-for-predictability-by-daniel-s-vacanti-re-read-saturday-week-10-flow-debt/#more-9151)
  while reviewing and commenting the book itself.
* *Effort Run Chart*, simply represent the inverse of the daily **WIP**
  (`1/WIP`) and, for this reason, shows, each day, the **Daily Effort**
  that is the time theoretically spent, such day, for each ongoing (both
  **Next** and **In-progress**) work item.

  For example: if the **WIP** value is 1, you theoretically spend 100%
  of your time on such work item. If you have 2 ongoing work items
  (`WIP = 2`) means that you theoretically spend half of the day for
  each work item, this means the effort for each work item is 50%. With
  5 work items, your **Daily Effort** for each work item is 20%, and so
  on.

Since the same data are sometimes shown in different charts, in order to
improve readability, the data always (try to) use the same colouring
throughout the charts in this sheet. So, for example, **mWIP** is always
an orange line, both in *Little's Law* and in *WIP Run Chart*, etc.

## Metrics
The [Metrics](#Metrics) sheet contains a set of metrics computed from
the data in [WorkItems](#WorkItems) sheet. Mainly, together with a few
duplication of information (work item **ID**, **Name**, and **Done**
date) for better reference and readability, for each row there is a work
item with the following metrics and columns.

To easily remember the content length, the formulas in this sheet are
spread till row number 3653, that is enough to manage 3652 work items. 
Feel free to increase the formulas coverage by dragging them to cover
more rows, when needed.

* **Backlog**, **Next** and **In-progress** columns that contain the
  number of days spent by the work item in each column. If the work item
  enters and exists a column on the same day, the count will show 0.
* the **95%**, **85%**, **70%**, **50%** columns that represent the
  moving percentile of the completed work items Lead Times. You can find
  a description of percentile in
  [Percentile](https://en.wikipedia.org/wiki/Percentile) page on
  Wikipedia. For more details, see [Actionable Agile Metrics for
  Predictability](https://leanpub.com/actionableagilemetrics) book.
* **LT** computes the Lead Time for each completed work item.
* **mLT** contains the daily moving average of all the Lead Times of
  the completed work items. Please note that this is the plain running
  average, done point-by-point by day.
* **Age** contains, for all not-completed work items, the number of days
  since the work item is in progress (since in entered in **Next**).
* **Blocked Days** contains the total number of days the work item has
  been blocked.
* **Impact** is computed (as described in [Kanban Maturity
  Model](https://www.kanbanmaturitymodel.com/) book), for a completed
  work item, by summing the total of blocked days of all previously
  **Done** work items (current included), divided by the number of
  work items. It represents the average number of blocker days per
  work item.
* **Likelihood** is computed (as described in [Kanban Maturity
  Model](https://www.kanbanmaturitymodel.com/) book), for a completed
  work item, by counting the total number of blockers of all previously
  **Done** work items (current included), divided by the number of
  work items. It represents the average probability of having a blocker
  per work item.
* **Computed Effort**, for a completed work item, considers, for each
  day of the progress life of the work item, the number of parallel work
  items ongoing in the system (that is, the daily WIP). e.g. While a
  single work item counts as 1 day of effort per day, if there are two
  parallel work items (WIP = 2), the actual effort, per work item, is
  1/2 (or half) day. So, summing up all these daily computed efforts,
  for the whole work item lifetime, this column contains the total
  number of days theoretically worked on the work items, blockers
  included.
* **Risk** is computed (as described in [Kanban Maturity
  Model](https://www.kanbanmaturitymodel.com/) book), for a completed
  work item, by multipling the Impact and the Likelihood. It represents
  the average number of blocker days that may appear in work items.
* **FE** (or Flow Efficiency) is computed, for each completed work item,
  as the total number of blocker days over the lead time. e.g. If a
  work item has been completed in 13 days but it has been blocked for 10
  days, its FE is 23,08%.
* **mFE** contains the daily moving average of all the Flow Efficiencies
  of the completed work items.

## Distribution
The [Distribution](#Distribution) sheet contains some set of data used
for previously described chart. Specifically, it contains the frequency
distributions and percentile value for **LT**, **Backlog** and
**Thr**oughput, as shown in [CFD](#CFD) and [Lead Time](#Lead%20Time)
dashboards.

* The **F(LT)** column contains the frequency related to lead times, the
  number of completed work items that had a lead time less than or equal
  to the **LT(bin)** column value. This table column is also plotted as
  histogram (*Lead Times Distribution* bar chart) showing the current
  distribution of lead time frequencies.

* The **F(Backlog)** column contains the frequency related to age of
  elements (days spent) in backlog, regardless they are still in backlog
  (so their age will increase) or they've already been moved to other
  columns. This is the number of work items that have/had a backlog age
  less than or equal to the **Backlog(bin)** column value. This table
  column is also plotted as histogram (*Backlog Age Distribution* bar
  chart) showing the current distribution of backlog ages frequencies.

* The **F(Thr)** column contains the frequency related to daily
  throughput values, the number of done work items for each day, less
  than or equal to the **Thr(bin)** column value. This table column is
  also plotted as histogram (*Throughputs Distribution* bar chart)
  showing the current distribution of throughputs frequencies.

* The Weibull columns (**Weibull(LT)**, **Weibull(Backlog)** and
  **Weibull(Thr)**) contain the computed values of the approximate
  Weibull distribution that mostly resemble the current distribution of
  values described by the **F(LT)**, **F(Backlog)** and **F(Thr)**
  columns. These table columns are also plotted as line overlapped to
  their specific distribution bar chart. The Weibull distributions are
  computed from the specific values of **Shape (k)** and **Scale (λ)**
  that have been approximated from the **Percentile(LT)**,
  **Percentile(Backlog)** and **Percentile(Thr)** values.

**Shape (k)** is computed from the 35p and 75p (percentile) values in
the **Percentile(LT)** column while **Scale (λ)** is computed from the
35p value and the **Shape**. I'd reference to Alexei Zheglov nice blog
post [How to Match to Weibull Distribution in
Excel](https://connected-knowledge.com/2013/08/01/how-to-match-to-weibull-distribution-in-excel/):
even though my calculations came from a different source (that I can't
actually remember, but still searching to give it a proper reference),
the results are similar to those written by Alexei in such post.

**Mean**, **Variance**, **Median**, **Mode** are computed according to
default Weibull distribution equation, using values of **Shape (k)** and
**Scale (λ)**. Together with this default values from a Weibull
distribution, there also are the **UCL** (Upper Control Limit) and
**LCL** (Lower Control Limit) for control chart purposes that might be
used in future charts.

* **Percentile(LT)** and **Percentile(Backlog)** columns represents the
current percentile values for Lead Time and Backlog age, the latter
being the number of days a work item remains in the Backlog (since it
has been created) before being took in charge and worked on;

* The **CoS** table shows the Classes of Services ratio with respect
  to the total number of work items. It uses the four standard Classes
  of Services, and the colours are those defined as examples in
  [Kanban](https://leankanban.com/shop/kanban-book/) book. It's the
  source of the *CoS Ratio* chart in the [CFD](#CFD) dashboard sheet.

## Data
The *Data* sheet is the daily representation of the whole board, with
reference metrics needed for each day (**Date** column). Together with
the daily number of work items for each column (**Backlog**, **Next**,
**In-progress**, **Done**), the sheet contains:

* the daily (cumulated) number of **Deleted** work items.
* the daily *Delivery Rate* (**DR**), the number of completed work items
  for the day, that is the number of work items moved to *Done* column
  and not deleted/discarded.
* the moving average delivery rate since the initial period (**mDR**).
* the daily **WIP**, the number of currently ongoing work items
  (**Next** plus **In-progress**).
* the moving average WIP since the initial period (**mWIP**).
* the moving average WIP of the latest seven days (**mWIP(7)**).
* the average lead time (**mLT**) computed as **mWIP** / **mThr**.
* the average lead time (**mLT(7)**) computed as **mWIP(7)** /
   **mThr(7)**.
* the actual **Daily Effort** per work item, as the multiplicative
  inverse of **WIP** (1 / **WIP**).
* the daily current **Thr**oughput as the number of done work items for
  the day, that is the number of work items moved to *Done* column.
* the daily **mThr** and **mArrival** moving averages rates for work
  items as described in [Actionable Agile Metrics for
  Predictability](https://leanpub.com/actionableagilemetrics) book (as
  "Incoming" and "Outgoing");
* the set of cumulative daily data of work items for each column
  (**Backlog**, **Next**, **In-progress**, **Done**);
* the Approximate Average Lead Time (**AALT**), computed as described in
  [Actionable Agile Metrics for
  Predictability](https://leanpub.com/actionableagilemetrics) book.

This chart contains data rows till spreadsheet row number 3653, that is
enough to run the board for ten average Gregorian years. 

## Appendix

### GNU Free Documentation License

Version 1.3, 3 November 2008

Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation,
Inc. <https://fsf.org/>

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

#### 0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.

This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense. It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does. But this License is not limited to software manuals; it
can be used for any textual work, regardless of subject matter or
whether it is published as a printed book. We recommend this License
principally for works whose purpose is instruction or reference.

#### 1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
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#### 2. VERBATIM COPYING

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#### 3. COPYING IN QUANTITY

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-   O. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or
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The author(s) and publisher(s) of the Document do not by this License
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#### 5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this
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Make the same adjustment to the section titles in the list of
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In the combination, you must combine any sections Entitled "History"
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#### 6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other
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You may extract a single document from such a collection, and
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License in all other respects regarding verbatim copying of that
document.

#### 7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
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When the Document is included in an aggregate, this License does not
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If the Cover Text requirement of section 3 is applicable to these
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#### 8. TRANSLATION

Translation is considered a kind of modification, so you may
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#### 9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document
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#### 10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the
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<https://www.gnu.org/licenses/>.

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#### 11. RELICENSING

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The operator of an MMC Site may republish an MMC contained in the site
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### ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
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