Tag Archives: Agile


This blog reflects my learning process, experiments, and personal experience helping software teams. I have worked with a bunch of exceptional professionals who have suffered many of my mistakes and they have replied to me delivering working software, putting more effort on software quality and even more energy to try new things. Several years ago I committed myself to understanding what software development actually is and how to help those professionals do their best. I think this blog is in the right direction, tirelessly, step-by-step I pay back to them and to the agile community what I owe them.

If you are wondering how my personal purpose and my unpaid debt is related to productivity keep reading. I am going to start by describing a team as a

“network of interconnected work”

Team members who are the nodes of the network, transform, exchange and convert raw information into value to customers. An important characteristic of these networks is that “work” has dependencies between nodes. An event or sequence of events must take place before another, however, the sequence is not predictable. It means that my productivity depends on many other nodes of the network.

In my opinion, many organisations have ignored this remarkable characteristic and they assess employee’s productivity individually without considering the environment. These organisations tend to avoid measuring productivity of the network as a whole.

            “You cannot improve what you cannot see.”

The situation gets more and more unfair when employees do not have either control or authority to change how they interact with the network. Edward Deming wrote 14th principles in his brilliant book Out of Crisis:

Remove barriers that rob people in management and in engineering of their right to pride of workmanship. This means, inter alia, abolishment of the annual or merit rating and of management by objective (see Ch. 3).

Another side effect of productivity is busyness. As all nodes of the network are busy, the whole system loses responsiveness and effectiveness needed to react to continuous changes happening around. Busyness organisations want to reach high level of capacity utilisation avoiding idle nodes. An exaggeration might be to create a buffer of work to do just before every node in order to avoid starvation. My untested hypothesis about the expected behaviour is in this case, a network with a poorer global performance and longer time to market. Work to do has to wait in a queue until the node has free capacity to work with it and to dispatch it to the next node of the network, which is also be terribly busy. Hence, work must wait in a queue again.

Not long ago a friend of mine told me that his manager had wanted their teams to achieve maximum capacity utilisation and velocity. Then POs began to take features from here and there to prepare an iteration backlog considering number of people, their skills, expertise and calendar days… It was an exaggeration. Wasn’t it?

“Watch the baton, not the runner”

Productivity and Variability

Software development systems are high variability systems affected by external and internal sources of variability. External sources of variability are mostly rules, policies and events at the organisation level:

  1. Technology: Using immature technology we are exposed to bugs or changes in our technology. For example, lean companies try to use only reliable and proven technology.
  2. Team organisation: Changing team members continuously imply that teams must reorganise and affects negatively their performance. People are not replaceable not exchangeable. Furthermore, space configuration and distance between nodes are barriers to our communication. The likelihood of communicating falls dramatically when distance is farther than 30 meters.
  3. Knowledge or business complexity: Lack of domain knowledge to solve the customer’s problems or constant changes in their preferences are also common sources of variability.
  4. Customer: Lack of involvement or weak support from the customer. When either feedback is too long or is useless from a proxy persona instead of the real customer we can build the wrong system.
  5. Competitors: Competitors’ decisions affect our plans when they bring new products into the market. We should react and inject variability in our project plans.
  6. Waiting for availability: is the time that work is idle waiting for other parts or nodes.
  7. Dependencies or specialisation: It is a significant self-wounded promoted by organisations that encourage high levels of specialisation. This “culture” lengthens our development time and our time to market. We are more exposed to changes in market preferences or competitors.

On the contrary, internal sources of variability are mostly focused on individuals. Intrinsic factors like motivation, healthy or safety among others are very dependent on how we see the world and affect our individual performance. Variability has an important effect on productivity so we might put strong and direct effort on reducing the bad economic consequences of those variability factors in order to increase productivity of the whole system.

Now, I am going to take a different approach and see how to assess productivity through the eyes of Theory of Constraints (TOC). The only goal of an organisation is to make money. Eddie Goldratt who designed TOC considered that Throughput is a powerful metric to measure organisation’s performance. Throughput is the rate at which the organisation converts its inventory of products into sales.

From the TOC perspective, the performance of the development process is affected by bottlenecks, which impede the organisation to achieve its goal. Performance of the whole system is determined by the capacity of those bottlenecks. System performs at the speed of the slowest link in the chain. Whether you increase the capacity utilisation on non-bottleneck nodes of your network, you are not improving the system at all.

“For any resource that is not a bottleneck, the level of activity from which the system is able to profit is not determined by its individual performance but by some other constraint within the system. – Eddie Goldratt”

TOC encourages you to either increase bottleneck’s capacity through improving its process, removing unnecessary work or deriving it to other areas of the system. Finally, we might add more people or required resources if previous actions didn’t achieve the expected results. In any case, we aim at improving the whole system in order to increase throughput.

This is the sequence of steps required to apply TOC:

  1. Identify the constraint
  2. Exploit the bottleneck
  3. Subordinate everything
  4. Elevate the constraint
  5. Avoid Inertia

In theory, TOC is a tool to strengthen the view of the system as a whole through implementing a global metric (throughput) and improving flow whereas avoiding local optimisations on resources that are not bottlenecks.


I hope to give you some arguments to discuss about productivity in your organisation.

  • Productivity has very harmful side effects for the organisation: longer time to market, waste created by busyness*.
  • Culture of busyness reduces responsiveness and effectiveness required to adapt continuously to changes. Network and world around us is not static but dynamic.
  • Identifying bottlenecks is the first step of TOC to improve throughput.
  • Many opportunities to improve the whole system are manager’s responsibilities.
  • Either removing unnecessary work or deriving it to other parts of the system is a good alternative to try to improve throughput.
  • Adding more capacity should be our last choice.
  • When you prioritise an iteration backlog based on ROI and some team members are idle, take advantage of these visible signals to discuss specialisation, t shape resources availability, team organisation and organisational culture.

This is what I have learnt so far and I wish to write in the future to contradict some of the arguments written here. That would be a signal to indicate that I learnt something new.

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Cost of Delay – Decision Making Framework

“Cost of delay is the language to translate value and impact to our customers into money. “

Cost of delay is the cornerstone of the economic decision making framework, which helps businesses to assess the impact of time on their products and to prioritise their scarce resources on them. Cost of delay puts the tag price on our features and assesses how their value decays over time.

Using cost of delay our discussions shift from the typical labor cost-oriented mindset in which the important topic is what the cost of the feature is to a radically different approach in which we assess the value of the piece of work to do in terms of impact to the business and customers. We model an economic scenario and consider it real when prioritising features or products in our portfolio. Notice that we are replacing gut feeling to using a more scientific model. This model is more adaptable to the complex adaptive system we have to deal with. We arrange experiments and hypothesis using “probe > sense > respond” to learn how the system responds to the stimulus. Cost of delay is a powerful vehicle to harmonise a single vision of the future and to align a common business strategy.

As we have just mentioned, cost of delay is strongly dependent on time and we should depict how time affects product development. @JoshuaJames reflects on 3 different profile life cycle development patterns to describe product development markets.

Short life cycle and sales peak is affected is cost of delay.

Screen Shot 2015-05-18 at 15.25.09

This urgency pattern has a very short life cycle and sales are profoundly affected by delay. Consider for example the challenge to release a mobile game. As soon as the product is released, sales ramp up very fast until reaches a peak. Then, sales progressively begin to decay. Life cycle is very short and peak is affected by delay. Whether we release our product too late, our peak is reduced due to the fact that market is almost covered by other titles. At a certain point, when sales begin to decay we must invest in discovering which features can help to stabilise or increase the revenue. An important characteristic of this profile is that exciting features (Kano model) are quickly copied by competitors and become basic needs future products.

Long life cycle and sales peak is affected by delay.

Screen Shot 2015-05-18 at 15.24.44

This life cycle profile for certain products also reflects a quick growth nevertheless sales maintain over time. In this case, the first company to introduce the product into the market wins the competitive advantage over latecomers. Cars market or competition between airplane manufacturers is good example of this kind of profile.

Long life cycle and sales are unaffected by delay.

Screen Shot 2015-05-18 at 15.25.00

This profile is the easiest one to compute due to profits are sustained over a long period of time. Number of sales is not affected by when the product is released.

Once, we have identified the urgency pattern it is time to decompose value and duration which are both parameters required to compute cost of delay.

The value of the product features was previously introduced here and has to be estimated considering 4 different perspectives:

  • Increase revenue reflects the revenue provided by new-delighted features (KANO model), which attract either new users or current users.
  • Protect revenue are small improvements which current users will not be able to not pay any extra money for.
  • Reduce cost are improvements in our process to deliver value faster.
  • Avoid cost: costs that are not incurring right now to occur in the future unless some action is taken.

Notice that these perspectives might be complementary and the total value is obtained summing these 4 areas.

Let’s take a hypothetical example. A small company that released a successful instant communication tool is researching on the profitability of adding new features.

           Feature: As a User, I want to use voice commands to request the application to dictate messages to the receiver.

Our network of daily active users is 5 millions. Current license price is $10. The marketing strategy is to offer an upgrade worth $5 to current users and hence we expect 10% of daily users to purchase it. We expect our immediate competitors to release their new service in 3 months so we expect to lose 8% of the revenue per month from current active users who would not pay the upgrade every month and 5% value depreciation of the network of users.

Increased Revenue:

We expect 2% rise in new revenues from users who will pay $5 for the new service.

= 2% 5M daily active users * $5 = $500K

Avoid Cost:

Releasing late this feature would decrease 8% of revenue from current users and would devaluate 5% the net value of our network every month. This network is worth $50M today.

= f(g) current users + f(i) network of users

= 8% 5M daily active users * $5 = $2M

= 5% $50M= $2,5M

COST OF DELAY = $500K + $2M + $2,5M $5M

So, cost of delay is the amount of money we will not make whether that feature is not released on time.


The amount of time required to release the feature or product to the customer is the second factor required to compute cost of delay. Notice that I prefer making statistical analysis about the performance of the system (historical data) rather than estimating duration.


So far, we have assessed the list of features in terms of value and duration, however, that is not enough to prioritize and maximise the economics. Product development contains features that usually have different value; urgency and duration so standard approaches like FIFO or LIFO are far from optimising economics. Rather we use cost of delay divided by Duration.

As you can see, cost of developing a product or a feature is not considered when prioritising. Why? First of all, Time is the most critical factor because it is irreplaceable. It cannot be replaced or reversed. On the contrary, funds can be obtained through external sources like financial capitalisation. Also, cost is not a good variable to consider when making decisions due to the asymmetric payoff function of product development. Cost is not proportional to the value obtained. Some research points out that only 30% or 40% of our features can provide up to 90% of the value and we usually only consider cost when making economic decisions. We don’t properly deal with variability and it force us to maximise economics by eliminating all choices with uncertain outcomes.

Finally, I have conscientiously removed the option of adding more capacity because its difficulty to scale in certain situations, especially in later stages of development. Most of the times, adding more capacity leads to communication overloads, and more delays.

            “If you bring new people to a product that is late, it’s likely to delay the project even more because of the increased complexity and the need for the team to adapt to its new composition”

Inspect and adapt

As our customer preferences change and competitors adapt their strategy, cost of delay is constantly affected. Our value model needs to be revisited and refined often. Hence, Cost of delay is not a static figure and urgency pattern is a way to create awareness and shared understanding about the economic impact of delays.

How to prioritize

In order to answer to this question, we have a list of features with different value, duration and CD3.

Feature Value Duration Cost of Delay
Feature A $10K 6m $1.6K
Feature B $8K 4m $2K
Feature C $27K 14m $1,92K

The optimal scheduling decision TODAY is to deliver the feature with highest CD3. So, first feature to release would be B, then C and then A.

Next 2 examples are very atypical in software development but it’s worth mentioning them.

When all features have the same value but different duration, very atypical in software development we might use shorter time first (SJF).

Feature Value Duration Cost of Delay
Feature A $10K 6m $1.6K
Feature B $10K 4m $2.5K
Feature C $10K 14m $0.71K

So, optimal selection would be: B, A, C.

When all features have the same duration but different value we might sequence the work to do with high cost of delay first (HDCF).

Feature Value Duration Cost of Delay
Feature A $30K 5m $6K
Feature B $20K 5m $4K
Feature C $10K 5m $2K

Optimal scheduling would be: A, B, C.

Finally, in Flow Product development we measure throughput as the rate at which we convert inventory through sales and value delivered to the customer. Thus cost of delay can be considered a healthy signal of the system. All partially completed features (inventory) are avoiding us reach the goal of making money.

“How much money and time do we spend on features that have not been converted into throughput?


  • Cost of delay puts a price tag on our features in order to help you maximise economics and prioritise.
  • Cost of delay shifts our mindset from cost and efficiency to speed and value.
  • Cost of delay assesses our value models against urgency, value and risk.
  • Not only Cost but also probability are required to make optimal economic decisions. Cost is not always proportional to the value obtained. Asymmetry payoff function of product development remind us that we need variability to create value and short feedback loops to cut wrong paths as soon as possible.
  • We consider 4 different perspectives to assess value:
    • Increase Revenue
    • Protect Revenue
    • Reduce Cost
    • Avoid Cost
  • Cost of Delay is an alternative way to assess the economic impact of the inventory of design in progress.
  • CD3 is a prioritisation algorithm for work to do with different urgency, value and duration.
  • Cost of delay can be obtained dividing value by duration.

This blog post is in some way an extract of the ideas developed by @JoshuaJames and Donald Reinertsen.

For further information see next sources of information:






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