The document discusses the "cone of uncertainty" concept in project management. It explains that the cone of uncertainty shows that estimates become more accurate as a project progresses from initial concepts to detailed design and completion. Early estimates can be off by a factor of 4, while later estimates are typically within 25% of the actual time or cost. The document provides tips on using the cone of uncertainty to set expectations and improve estimates over time through discovery and reducing assumptions.

1. Monsoon rains for more
areas in Luzon on Friday
Monsoon rains may trigger flashfloods and landslides in Ilocos Region,
Benguet, and the islands of Batanes, Calayan and Babuyan
Rappler.com
Published 6:38 PM, July 16, 2015
Updated 6:38 PM, July 16, 2015
What's the weather like in your area? Tweet us the situation: Use
#weatheralert and tag @rapplerdotcom
MTSAT ENHANCED IR satellite image, 5:32 pm, July 16. Image courtesy of PAGASA
MANILA, Philippines – More areas in Luzon will experience monsoon rains on
Friday, July 17, said state weather bureau PAGASA.

2. In its 5 pm bulletin Thursday, July 16, PAGASA said the monsoon rains
maytrigger flashfloods and landslides in Ilocos Region, Benguet, and the
islands of Batanes, Calayan and Babuyan.
A southwest monsoon is still affecting Luzon.
Cagayan Valley and the provinces of Bataan and Zambales will have
occasional rains, while Metro Manila and the rest of the country will have
partly cloudy to cloudy skies with isolated thunderstorms.
Moderate to strong winds from the southwest will prevail over Luzon and
Visayas, causing moderate to rough waters. Elsewhere, coastal waters will be
slight to moderate as light to moderate winds blow also from the southwest.
City Forecast
Temperature
Range
Metro Manila Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
28°C-31°C
Tuguegarao Occasional rains 25°C-32°C
Laoag Monsoon rains 24°C-27°C
Baguio Monsoon rains 16°C-18°C
Subic/Olongapo;
Clark/Angeles
Occasional rains 27°C-29°C
Tagaytay Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
21°C-26°C

3. Lipa Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
27°C-31°C
Legazpi
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-33°C
Puerto Princesa Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
25°C-30°C
Iloilo/Bacolod Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-33°C
Metro Cebu
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
25°C-32°C
Tacloban
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-33°C
Cagayan de Oro Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
24°C-32°C
Metro Davao Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-33°C
Zamboanga
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
23°C-32°C

4. LPA spotted off Batanes
Batanes and other parts of Luzon will continue to experience monsoon rains.
A southwest monsoon is still affecting Luzon
Rappler.com
Published 6:32 PM, July 17, 2015
Updated 6:32 PM, July 17, 2015
What's the weather like in your area? Tweet us the situation: Use
#weatheralert and tag @rapplerdotcom
MTSAT ENHANCED IR satellite image, 5:01 pm, July 17. Image courtesy of PAGASA
MANILA, Philippines – State weather bureau PAGASA spotted a low pressure
area (LPA) off Batanes on Friday afternoon, July 17.
As of 4 pm, the LPA was estimated at 905 km east northeast of Basco,
Batanes. Monsoon rains may trigger flashfloods and landslides in the island,

5. as well as inIlocos Region, Benguet, Central Luzon, and the islands of
Calayan and Babuyan.
A southwest monsoon is still affecting Luzon.
Metro Manila, Calabarzon, and the rest of Cordillera and Cagayan Valley will
have occasional rains, while the rest of the country will have partly cloudy to
cloudy skies with isolated thunderstorms.
Moderate to strong winds from the southwest will prevail over Luzon and
Visayas, causing moderate to rough waters. Elsewhere, coastal waters will be
slight to moderate as light to moderate winds blow also from the south to
southwest.
City Forecast
Temperature
Range
Metro Manila Occasional rains 26°C-30°C
Tuguegarao Monsoon rains 24°C-29°C
Laoag Monsoon rains 24°C-27°C
Baguio Monsoon rains 16°C-18°C
Subic/Olongapo;
Clark/Angeles
Monsoon rains 23°C-28°C
Tagaytay Occasional rains 21°C-26°C

6. Lipa Occasional rains 26°C-31°C
Legazpi
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-31°C
Puerto Princesa Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
25°C-31°C
Iloilo/Bacolod Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
26°C-30°C
Metro Cebu
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
25°C-32°C
Tacloban
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
25°C-32°C
Cagayan de Oro Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
24°C-32°C
Metro Davao Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
27°C-32°C
Zamboanga
Partly cloudy to cloudy skies with isolated
rainshowers or thunderstorms
23°C-33°C

7. What is the cone of uncertainty?


 inShare
The cone of uncertainty is the shape made by graphing the
accuracy of estimates against the stage of the project. It
embodies the idea that estimates made at the beginning of a
project will be limited in their accuracy, and that if you work to
reduce uncertainty in the project, the estimates can become more
accurate over the course of the project.
By understanding the cone of uncertainty you can understand why your initial
project estimates will not be accurate, and how you can improve them. You can
also use the cone of uncertainty to defend your estimates if they are called into
question at a later date. You can also use the cone of uncertainty to support
initial discovery stages of projects, where the project concept, requirements and

8. design are fleshed out to give a better idea of project feasibility, schedule and
cost.
The cone of uncertainty shows the best case accuracy of estimates made at different times in the
projects life.
Estimates can only be as accurate as the assumptions they are based on. If your
project is to build a bridge, but you are not yet sure how many lanes of traffic it
will take, your estimates about the bridge cannot be particularly accurate.
Studies of software projects have shown that at the beginning of a project, even
the best estimators are commonly mistaken in their estimates by a factor of 4.
This means if they estimate the project will take a month, it could take as little as
one week, or as much as four months. Later, once detailed design is complete

9. much more accurate estimates can be produced, perhaps with less than a factor
of two error.
By the way, this is the best case scenario with very accurate estimators! Most
people cannot estimate this well, so estimates will likely be even less accurate.
Why is this initial estimateso inaccurate?
Because any estimate is based upon assumptions. At the beginning of the
project there are many unresolved questions. What are the requirements? How
many people will be available to work on the project? What skill level will the
people have? and many others.
Each unresolved question must have an assumed answer to produce any kind of
estimate. The accuracy of these assumptions directly contributes to the accuracy
of the estimate.
Throughout the course of the project many of these assumptions can be replaced
with actual answers. Doing so reduces the uncertainty in the project and allows
better estimates to be provided.
For instance once it is decided to provide a bridge for two lanes of traffic (instead
of a single lane or four) cost and effort estimates can be greatly refined. This is
an example of reducing uncertainty by clarifying project requirements.
When should you commit to estimates?
The cone of uncertainty tells us that any estimates made early in the project will
be wildly innacurate in the best case. Thus you should only make commitments
based on estimates once you are further through the project.

10. You should delay committing to estimates as long as possible. Ideally the
requirements gathering and design phase should both be complete before
committing to estimates. This will produce the most accurate estimates.
Unfortunately clients and project sponsors usually want firm commitments at the
very beginning of projects. This is the worst possible time to make estimates.
According to the cone of uncertainty, any estimate you give will very likely be off
by a factor of 4, which will cause anger and distrust between the project team
and the client/sponsor.
If you are under pressure to provide estimates and commitments, attempt to
negotiate a discovery phase of the project. During this phase the product
definition can be clarified, requirements gathered and high level design sketched
out. This gives a much better basis to estimate the project on. The cost of this
phase can be charged to the prospective client, or if necessarily absorbed by the
project team.
If a customer/sponsor refuses to allow a discovery phase, you should at the very
least communicate the uncertainty in your estimates to the customer. The best
way to communicate the uncertainty is to give the estimate using a range. For
example, instead of estimating 1 month, you can estimate 1 week to 4 months.
By giving an upper and lower bound on your estimate you can clearly
communicate the uncertainty inherent in the estimate. If the person receiving the
estimate is unhappy with the range given, you can use it to request more time or
resources to resolve some of the ambiguity and create tighter estimates.
As you proceed through the project you can reduce uncertainty and thus produce
better estimates. However, this does not happen automatically! If you wish to
produce better estimates you need to continually work to resolve any
assumptions and update estimates to reflect this.

11. Note that the assumptions are a source of uncertainty, they are often related to a
project risk. Thus the project risk register is a good place to track assumptions
upon which the projects estimates are based. This also gives a central place to
review to find opportunities to improve estimates. This can be performed in the
periodic project risk review meetings.
TaskTrakz allows you to express estimates as ranges and track your risks in
acentralized risk register. Expressing estimates as a two or three point range for
each work item allows an estimate range to be calculated for the whole project.
You can accurately communicate the uncertainty inherent in your project to
project stakeholders, setting their expectations accordingly.
TaskTrakz provides you with the tools to track and present your estimates. Get
your free 14 day trial of TaskTrakz today.

12. DAY COND HIGH LOW DESCRIPTION PRECIP WIND
The Cone of Uncertainty
The Cone of Uncertainty is a phenomenon known for some time, but it only started to
become accepted in software development during the past decade, primarily because of
the rise of agile methodologies.
Definition
In project management, the cone of uncertainty describes the graph that gives estimate
variability over time. The level of accuracy of a given estimate increases over time (the
variability decreases), when you work towards the end of the project. This might seem
obvious, but it’s often ignored by business owners and managers who demand an
accurate estimate even before the project started. The ‘Theory of the Cone’ shows that
you can NEVER provide an accurate estimate, but should rather provide a range. This
range can be used as an aid (but not the only one!) for planning and budgeting
purposes.
This means that you can only give accurate estimates when you’re nearing the end of
the project. In the beginning of the project, when the scope isn’t yet well defined and
some, or even most, of the requirements are still a bit ambiguous, you’re better off with
providing a range.
The following graphs shows the cone in all of its glory:

13. This graphs shows that any estimate given at the time of the initial concept might be 4x
off, positive or negative. A concept estimated to take 6 months, might therefore take any
time between 2 years and 2 months…
At the point where all the requirements are known (and assuming that they won’t
change, so this is clearly a theoretical exercise for now…) this estimate might turn out to
become anything between 9 and 4 months.
When the detailed design is ready, the same estimate will be within the range of 7,5 and
4,8 months (between 1.25x and 0.8x, where x=6 (months)).
How to use the cone in your advantage ?
In order to cope with “the reality of the cone”, you should convince the project’s
stakeholders that it’s better to spend some money at the beginning of the project, so
that the estimate given later on will have a smaller range of variability.

14. In other words: spend 3-4 iterations and review the estimate so that the range of
variability becomes smaller. In a proper agile approach, the high risk items will be
covered during the first iterations anyway.
Sunny Day vs. Rainy Day
In order to provide both sunny and rainy day estimates at any given time during the
project, you can just use the maximum and minimum of the cone, depending on where
you are in your project schedule.
In the beginning of the project, the sunny day and rainy day scenario’s can be months
apart from each other. Nearing the end, the difference can be a matter of days
(depending on overall project size).
Risk, buffering and padding
The cone doesn’t take all risk into account. Don’t rely on the cone as the only way to
visualize risk!
The Wormhole of Uncertainty
The ‘Wormhole of Uncertainty’ looks like this:

15. As you can see, this graph starts as a cone, but never converges. The reason for this is
that last minute bugs are found, and keep on being found, resulting in the estimate to
remain unclear, and with a high degree of variability. If this situation is not turned
around, the project will either go on forever, or will end with too many remaining bugs in
the final release.
How to prevent the Wormhole ?
The wormhole can be prevented by following the tips below:
 Test-driven development will help to write good unit tests early in the process
 Automated testing will improve the results of user level testing and regression testing
 Frequent code check-ins combined with proper continuous integration will keep your code base
stable and bug-free
 Customer engagement throughout the process will make sure that the focus of the development
efforts remains aligned with customer vision
 Deploy early releases as often and as early possible in front of the customers
All of these recommendations have AGILE written all over them.
The nature of a traditional ‘waterfall’ project results in a higher risk for a cone that
doesn’t converge. The risks of too many bugs, or unexpected requirement changes at
the end of the project are just too high.
This is one of the explanations why traditional project approaches have a much higher
failure rate than the agile ones.