Does Your Demand Planning Process Include a “Quantitative Sanity Range Evaluation”?

There is a process that should be part of both your demand planning and your sales and operations planning.  The concept is simple – how do you find the critical few forecasts that require attention, so that planner brainpower is expended on making a difference and not hunting for a place to make a difference?  I have heard this process called a “Forecast Reality Check” and a “Forecast Reasonability Check”.  Just to be difficult, I’ll call it a Quantitative Sanity Range Evaluation (I have my own reasons.)  It may be similar in some ways to analyzing “forecastability” or a “demand curve analysis”, but different in at least one important aspect – the “sanity range” is calculated through bootstrapping (technically, you would be bootstrapping a confidence interval, but please allow me the liberty of a less technical name – “sanity range”).  A QSRE can be applied across industries, but it’s particularly relevant in consumer products, where I have seen a version of this implemented first hand by Allan Gray, a really smart gentleman – back when I worked with him for End-to-End Analytics – just so you know I didn’t think this all up on my own!

At a minimum, QSRE must consider the following components:

  1. Every level and combination of the product and geographical hierarchies
  2. A quality quantitative forecast
  3. A sanity range out through time
  4. Metrics for measuring how well a point forecast fits within the sanity range
  5. Tabular and graphical displays that are interactive, intuitive, always available, and current.

If you are going to attempt to establish a QSRE, then I would suggest five best practices:

1.  Eliminate duplication.  When designing a QSRE process (and supporting tools), it is instructive to consider the principles of Occam’s razor as a guide:

– The principle of plurality – Plurality should not be used without necessity

– The principle of parsimony – It is pointless to do with more what can be done with less

These two principles of Occam’s razor are useful because the goal is simply to flag unreasonable forecasts that do not pass a QSRE, so that planners can focus their energy on asking critical questions only about those cases.

2. Minimize human time and effort by maximizing the power of cloud computing.  Leverage the fast, ubiquitous computing power of the cloud to deliver results that are self-explanatory and always available everywhere, providing an immediately understood context that identifies invalid forecasts. 

3. Eliminate inconsistent judgments By following #1 and #2 above, you avoid inconsistent judgments that vary from planner to planner, from product family to product family, or from region to region.

4. Reflect reality.  Calculations of upper and lower bounds of the sanity range should reflect the fact that uncertainty grows with each extension of a forecast into a future time period.  For example, the upper and lower limits of the sanity range for one period into the future should usually be narrower than the limits for two or three periods into the future.  These, in turn, should be narrower than the limits calculated for more distant future periods.  Respecting reality also means capturing seasonality and cyclical demand in addition to month-to-month variations.  A crucial aspect of respecting reality involves calculating the sanity range for future demand from what actually happened in the past so that you do not force assumptions of normality onto the sanity range (this is why bootstrapping is essential).  Among other things, this will allow you to predict the likelihood of over- and under-shipment.

5. Illustrate business performance, not just forecasting performance with sanity ranges.  The range should be applied, not only from time-period to time period, but also cumulatively across periods such as months or quarters in the fiscal year.

If you are engaged in demand planning or sales and operations planning, I welcome to know your thoughts on performing a QSRE.

Thanks again for stopping by Supply Chain Action.  As we leave the work week and recharge for the next, I leave you with the words of John Ruskin:

“When skill and love work together, expect a masterpiece.”

Have a wonderful weekend!

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The Potential for Proven Analytics and Planning Tools in Healthcare Delivery

I’ve spent time in a hospital.  I was well cared for, but I didn’t like it, and I worried about the cost and how well I would be able to recover (pretty well, so far!)  Also, my daughter is a doctor (obviously takes after her mom!), so healthcare is obviously an area of high interest for me.

To say that managing a large, disaggregated system such as healthcare delivery with its multitude of individual parts, including patients, physicians, clinics, hospitals, pharmacies, rehabilitation services, home nurses, and more is a daunting task would be an understatement.

Like other service or manufacturing systems, different stakeholders have different goals, making the task even more challenging.

Patients want safe, effective care with low insurance premiums. 

Payers, usually not the patient, want low cost. 

Health care providers want improved outcomes, but also efficiency.

The Institute of Medicine has identified six quality aims for twenty-first century healthcare:  safety, effectiveness, timeliness, patient-centeredness, efficiency, and equity.  Achieving these goals in a complex system will require an holistic understanding of the needs and goals of all stakeholders and simultaneously optimizing the tradeoffs among them.

This, in turn, cannot be achieved without leveraging the tools that have been developed in other industries.  These have been well-known and are summarized in the table below.

While the bulk of the work and benefits related to these tools will lie at the organization level, such techniques can be applied directly to healthcare systems, beginning at the environmental level and working back left down to the patient, as indicated by the check marks in the table.

A few examples of specific challenges that can be addressed through systems analysis and planning solutions include the following:

1 – Optimal allocation of funding

2 – Improving patient flow through rooms and other resources

3 – Capacity management and planning

4 – Staff scheduling

5 – Forecasting, distributing and balancing inventories, both medical/surgical and pharmaceuticals

6 – Evaluation of blood supply networks

Expanding on example #5 (above), supply chain management solutions help forecast demand for services and supplies and plan to meet the demand with people, equipment and inventory.  Longer term mismatches can be minimized through sales and operations planning, while short-term challenges are addressed with inventory rebalancing, and scheduling.

Systems analysis techniques have been developed over many years and are based on a large body of knowledge.  These types of analytical approaches, while very powerful, require appropriate tools and expertise to apply them efficiently and effectively.  Many healthcare delivery organizations have invested in staff who have experience with some of these tools, including lean thinking in process design and six-sigma in supply chain management.  There are also instances where some of the techniques under “Optimizing Results” are being applied, as well as predictive modeling and artificial intelligence.  But, more remains to be done, even in the crucial, but less hyped, areas like inventory management.  Some healthcare providers may initially need to depend on resources external to their own organizations as they build their internal capabilities.

I leave you with a thought for the weekend – “Life is full of tradeoffs.  Choose wisely!”

Forecasting vs. Demand Planning

Often, the terms, “forecasting” and “demand planning”, are used interchangeably. 

The fact that one concept is a subset of the other obscures the distinction. 

Forecasting is the process of mathematically predicting a future event.

As a component of demand planning, forecasting is necessary, but not sufficient.

Demand planning is that process by which a business anticipates market requirements.  

This certainly involves both quantitative and qualitative forecasting.  But, demand planning requires holistic process that includes the following steps:

1.      Profiling SKU’s with respect to volume and variability in order to determine the appropriate treatment:

For example, high volume, low variability SKU’s will be easy to mathematically forecast and may be suited for lean replenishment techniques.  Low volume, low variability items maybe best suited for simple re-order point.  High volume, high variability will be difficult to forecast and may require a sophisticated approach to safety stock planning.  Low volume, low variability SKU’s may require a thoughtful postponement approach, resulting in an assemble-to-order process.  This analysis is complemented nicely by a Quantitative Sanity Range Evaluation, which should be an on-going part of your forecasting process.

2.       Validating of qualitative forecasts from among functional groups such as sales, marketing, and finance
3.       Estimation of the magnitude of previously unmet demand
4.       Predicting underlying causal factors where necessary and appropriate through predictive analytics
5.       Development of the quantitative forecast including the determination of the following:

  • Level of aggregation
  • Correct lag
  • Appropriate forecasting model(s)
  • Best settings for forecasting model parameters
  • Deducting relevant consumption of forecast

6.      Rationalization of qualitative and quantitative forecasts and development of a consensus expectation
7.      Planning for the commercialization of new products
8.      Calculating the impact of special promotions
9.      Coordinating of demand shaping requirements with promotional activity
10.    Determination of the range and the confidence level of the expected demand
11.    Collaborating with customers on future requirements
12.    Monitoring the actual sales and adjusting the demand plan for promotions and new product introductions
13.    Identification of sources of forecast inaccuracies (e.g. sales or customer forecast bias, a change in the data that requires a different forecasting model or a different setting on an existing forecast model, a promotion or new product introduction that greatly exceeded or failed to meet expectations).

The proficiency with which an organization can anticipate market requirements has a direct and significant impact on revenue, margin and working capital, and potentially market share.  However, as an organization invests in demand planning, the gains tend to be significant in the beginning of the effort but diminishing returns are reached much more quickly than in many other process improvement efforts.

This irony should not disguise the fact that significant ongoing effort is required simply to maintain a high level of performance in demand planning, once it is achieved.

It may make sense to periodically undertake an exercise to (see #1 above) in order to determine if the results are reasonable, whether or not the inputs are properly being collected and integrated, and the potential for additional added value through improved analysis, additional collaboration, or other means.

I’ll leave you once again with a thought for the weekend – this time from Ralph Waldo Emerson:

“You cannot do a kindness too soon, for you never know how soon it will be too late.”

Thanks for stopping by and have a wonderful weekend!

Resilience Versus Agility

Just a short thought as we move into this weekend . . .

Simple definitions of resiliency and agility as they relate to your value network might be as follows:

Resiliency:  The quality of your decisions and plans when their value is not significantly degraded by variability in demand and/or changes in your competitive and economic environment.

Agility:  The ability to adjust your plans and execution for maximum value by responding to the marketplace based on variability in demand and/or changes in your competitive and economic environment.

You can take an analytical approach that will make your plans and decisions resilient and also give you insights into what you need to do in order to be agile.

You need to know the appropriate analytical techniques and how to use them for these ends.

A capable and usable analytical platform can mean the difference between knowing what you should do and actually getting it done.

For example, scenario-based analysis is invaluable for understanding agility, while range-based optimization is crucial for resiliency.

Do you know how to apply these techniques?

Do you have the tools to do it continuously?

Can you create user and manager ready applications to support resiliency and agility?

Finally, I leave you with this thought from Curtis Jones:  “Life is our capital and we spend it every day.  The question is, what are we getting in return?”

Thanks for stopping by.  Have a wonderful weekend!

Metrics, Symptoms and Cash Flow

Metrics can tell us if we are moving in the right or wrong direction and that, in itself, is useful.  However, metrics by themselves do not help us assess our competitive position or aid us in prioritizing our efforts to improve.

To understand our competitive position, metrics need to be benchmarked against comparable peers. Benchmarking studies are available, some of them free.  They tell us where we stand relative to others in the industry, provided the study in question has sufficient other data points from your industry (or sub-industry segment).

Many times, getting relevant benchmarks proves challenging.  But once we have the benchmarks, then what?

Does it matter if we do not perform as well as the benchmark of a particular metric?  If that metric affects revenue growth, margins, return on assets, or available capital, it may matter significantly.

But, we are left to determine how to improve the metrics and with which metrics to start.  

Consider an alternative path.  Begin with the undesirable business symptoms that keep you up at night and give you that bad feeling in the pit of your stomach.

Relate business processes to symptoms and map potential root causes within each business process to undesirable business symptoms.

Multiple root causes in multiple business processes can relate to a single symptom.  On the other hand, a single root cause may be causing multiple undesirable symptoms.  Consequently, we must quantify and prioritize the root causes.

“Finding the Value in Your Value Network” outlines a straightforward, systematic approach to prioritizing and accelerating process improvements.  I hope you will take a look at that article and let me know your thoughts.

Thanks for having a read.  Remember that “You cannot do a kindness too soon, for you never know how soon it will be too late.”

Have a wonderful weekend!

Ten Key Questions for Spare Parts Planning

1)      How does demand behave?  To answer this, you must ask yourself the following:

a) How often do you expect to receive a demand for a given spare part?

b) What is the expected magnitude of a demand transaction when it occurs?

c) Are  failures based on age, or use, or both?

d) How large is the installed base of a given spare part?

(Technical note:  Historical data on the time interval between demands (inter-demand interval) and on the order of magnitude of demand transactions (demand order sizes) can be used to estimate the likelihood of a demand occurring in a given time interval and its transaction size using statistical techniques such as Croston’s method or a compound Poisson distribution[i].  If failure of a part (and the subsequent need for replacement or repair) is time-dependent (as many are), then the combined use of a type of Erlang distribution to estimate the interval and a Poisson distribution to estimate the quantity may be more appropriate.[ii])

2)      Are some spare parts much more important than others?  Some of the key questions here include the following:

a)  How expensive is the item?

b)  What does it cost to store and transport the item?

c)  What are the consequences when the part fails?

d) Do the consequences of a failure compound with time?

Factors like these are used to determine a part’s “criticality”.  For more critical parts, you usually need to have more safety stock.  That buffer stock may need to be geographically distributed near potential sources of demand and/or expedited delivery may be necessary.

(Technical note:  Where the answer to “d.” above is “yes”, then the use of an Erlang distribution may be helpful to estimate the duration of the wait time for the customer.)

3)      Is demand affected by the conditions in which the part is used and/or the level of preventative maintenance that it receives?  In cases where the answer is “yes”, then the algorithms and statistical approaches that are used to calculate demand and inventory requirements may need to be tailored for different situations.

4)      Are the magnitude and sources of demand such that requirements can be modeled as a trend over time with appropriate adjustments for seasonality?  If so, then this simplifies the planning considerably in that the requirements for such a spare part may be able to be modeled in a way that is similar to non-spare parts.

5)      Is the supply network composed of a single stage or multiple echelons?  The calculations for safety stock are different for each structure.

6)      Are the failed parts scrapped (consumed) or repaired and used again?  Where parts to be replaced are repaired and used again, a determination must be made as to whether the failed part is beyond repair and should be scrapped.  When new replacement parts should be purchased must also be determined, and tracking by serial number is required.

7)      Are the purchase, or manufacturing, batch sizes significantly larger than the expected demand quantities in a period?  If so, then this should be taken into account when planning resupply and safety stock.

8)      Is the supply constrained by a budget?  If so, you should take this into consideration when planning supply as well.

9)      Will requirements be reviewed periodically or continuously?  Continuous (or nearly continuous) review systems are quite feasible with modern communications and computing technology, and in many, if not most cases, they can yield better results.  A continuous review system reevaluates supply requirements each time an actual demand is generated.  Where a large number of spare parts must be monitored by a limited number of planners, however, it may be more practical to periodically review requirements (once per inter-demand interval or some multiple/fraction of inter-demand interval) for non-critical items and plan safety stock to account for demand variability over lead-time and the review period as well as variability in lead-time for those non-critical items.  Critical items, particularly expensive ones, should probably be evaluated continuously.  It may be useful to segment spare parts by levels of criticality and treat each group of parts accordingly.

10)   How many time periods of inventory do I currently have on hand for each spare part and for each category of spare parts?

A fundamentally sound approach to spare parts management can be summarized as follows:

  1. Understand your demand patterns
  2. Classify your parts (e.g. by criticality, by demand pattern, and/or cost, etc.)
  3. Apply the appropriate forecasting model and statistics
  4. Employ an efficient algorithm to find inventory targets and purchase quantities that meets the specific needs, constraints, and goals of your business including the structure of your value network, requirements of your customers, and the costs and risks/uncertainties that you face.  Keep the approach as simple as possible within those conditions.

(Note:  Many formal statistical approaches require assumptions that may not hold in your business.  In most cases, a heuristic that searches for a high value solution that conforms to real-world constraints, leveraging statistical theory where appropriate, is the most useful approach. )

5.  Deploy this algorithm through an easy-to-use, fast, visual and interactive tool that functionally meets your specific requirements, but  doesn’t “break the bank”.

As we enter this weekend, I leave you with one more thought — this time, from Socrates:  “The wisest man is he who knows his own ignorance.

Have a wonderful weekend!


[i] Lengu, D., Syntetos, A., Babai, M., “Spare Parts Management:  A Distribution-based Approach”, Salford Business School Working Paper Series, 342/11.

[ii] Saidane, S., Babai, M., Aguir, S., Korbaa, O., “Spare Parts Inventory Systems under an Increasing Failure Rate Demand Interval Distribution”, Proceedings of the 41st International Conference on Computers and Industrial Engineering,  2011.

Thoughts from IBF Conference

I just left the IBF’s Leadership Business Planning & Forecasting Forum and the Supply Chain Planning & Forecasting:  Best Practices Conference in Orlando, Florida.  I’ll share a few of the thoughts that struck me as helpful here in the hopes that they will help you.

From a panel discussion on organizational design at the Forum, I compiled this key point (adding in my own twist):   S&OP is all about integrated decision-making, understanding inter-related tradeoffs, driving toward bottom-line metrics with cause/effect accountability.

Rick Davis from Kellogg pointed out that  “Integrated planning is less about function than about process.

Rick also emphasized managing the inputs, particularly since data and technology are moving at the “speed of mind”.  Decision-makers need to ask themselves, “Will competitors leverage information better than I will?”

A few keys to success in S&OP include the following (see Ten Sins of S&OP for what NOT to do):

1)      Scenario analysis

2)      Leadership buy-in

3)      Quality feeder processes (my point of view)

4)      Remembering that financial targets and demand plans are different

Rafal Porzucek defined supply chain agility this way:  “The speed to react with predictable costs and service delivery.”  I thought that was pretty good.

The consumer products executives felt that the effort to leverage social media for forecasting was in the data collection phase.  In a couple of years, it may be useful for generating more accurate forecasts.

Mark Kremblewski and Rafal Porzucek from P&G made a compelling case for enabling innovation through standardization – and it made great sense.

Mark also shared a profound understanding of how the key numbers of business objective, forecast and actual shipments relate to each other.

I hope some of these points stimulate your thinking as they did mine.

There were other speakers who shared some great insights.  The absence of mention here is not meant to diminish their contribution.

This week, in the theme of anticipating the future, I leave you with the words of the English novelist and playwright, John Galsworthy, who won the 1932 Nobel Prize in Literature, “If you do not think about the future, you cannot have one.

Have a wonderful weekend!

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