The Objectives in Forecasting

A forecast is a prediction about the value of a time series variable at some time in the future. For instance, one might want to estimate next month’s sales or demand for a product item. A time series is a sequence of numbers recorded at equally spaced time intervals; for example, unit sales recorded every month.

The objectives you pursue when you forecast depend on the nature of your job and your business. Every forecast is uncertain; in fact, there is a range of possible values for any variable you forecast. Values near the middle of this range have a higher likelihood of actually occurring, while values at the extremes of the range are less likely to occur. The following figure illustrates a typical distribution of forecast values.

forecast distribution of forecast values

Illustrating a forecast distribution of forecast values

 

Point forecasts

The most common use of forecasts is to estimate a sequence of numbers representing the most likely future values of the variable of interest. For instance, suppose you are developing a sales and marketing plan for your company. You may need to fill in 12 cells in a financial spreadsheet with estimates of your company’s total revenues over the next 12 months. Such estimates are called point forecasts because you want a single number (data point) for each forecast period. Smart Demand Planner’ Automatic forecasting feature provides you with these point forecasts automatically.

Interval forecasts

Although point forecasts are convenient, you will often benefit more from interval forecasts. Interval forecasts show the most likely range (interval) of values that might arise in the future. These are usually more useful than point forecasts because they convey the amount of uncertainty or risk involved in a forecast. The forecast interval percentage can be specified in the various forecasting dialog boxes in the Demand Planning SoftwareEach of the many forecasting methods (automatic, moving average, exponential smoothing and so on) available in Smart Demand Planner allow you to set a forecast interval.

The default configuration in Smart Demand Planner provides 90% forecast intervals. Interpret these intervals as the range within which the actual values will fall 90% of the time. If the intervals are wide, then there is a great deal of uncertainty associated with the point forecasts. If the intervals are narrow, you can be more confident. If you are performing a planning function and want best case and worst case values for the variables of interest at several times in the future, you can use the upper and lower limits of the forecast intervals for that purpose, with the single point estimate providing the most likely value. In the previous figure, the 90% forecast interval extends from 3.36 to 6.64.

Upper percentiles

In inventory control, your goal may be to make good estimates of a high percentile of the demand for a product item. These estimates help you cope with the tradeoff between, on the one hand, minimizing the costs of holding and ordering stock, and, on the other hand, minimizing the number of lost or back-ordered sales due to a stock out. For this reason, you may wish to know the 99th percentile or service level of demand, since the chance of exceeding that level is only 1%.

When forecasting individual variables with features like Automatic forecasting, note that the upper limit of a 90% forecast interval represents the 95th percentile of the predicted distribution of the demand for that variable. (Subtracting the 5th percentile from the 95th percentile leaves an interval containing 95%-5% = 90% of the possible values.) This means you can estimate upper percentiles by changing the value of the forecast interval. In the figure, “Illustrating a forecast distribution”, the 95th percentile is 6.64.

To optimize stocking policies at the desired service level or to let the system recommend which stocking policy and service level generates the best return, consider using Smart Inventory Optimization.   It is designed to support what-if scenarios that show predicted tradeoffs of varying inventory polices including different service level targets.

Lower percentiles

Sometimes you may be concerned with the lower end of the predicted distribution for a variable. Such cases often arise in financial applications, where a low percentile of a revenue estimate represents a contingency requiring financial reserves. You can use Smart Demand Planner in this case in a way analogous to the case of forecasting upper percentiles. In the figure, “Illustrating a forecast distribution” , the 5th percentile is 3.36.

In conclusion, forecasting involves predicting future values, with point forecasts offering single estimates and interval forecasts providing likely value ranges. Smart Demand Planner automates point forecasts and allows users to set intervals, aiding in uncertainty assessment. For inventory control, the tool facilitates understanding upper (e.g., 99th percentile) and lower (e.g., 5th percentile) percentiles. To optimize stocking policies and service levels, Smart Inventory Optimization supports what-if scenarios, ensuring effective decision-making on how much to stock given the risk of stock out you are willing to accept.

 

 

 

Smart Software Announces Strategic Partnership with Sage for Inventory Optimization and Demand Forecasting

Belmont, MA, February  2024 –Smart Software, a global provider of next-generation cloud-based inventory optimization, demand planning, and forecasting solutions, announces today their strategic partnership with Sage.

This collaboration brings Smart IP&O (Inventory Planning and Optimization) into the latest cloud and on-premises versions of Sage X3, Sage 300, and Sage 100. By seamlessly integrating strategic planning with operational execution, users can eliminate reactive inventory planning and forecast guesswork by accurately calibrating risks, tradeoffs, and consequences at scale with Smart IP&O.

Sage is the leader in accounting, financial, HR and payroll technology for small and mid-sized businesses (SMBs). Customers trust Sage’s comprehensive suite of finance, HR, and Supply Chain software to streamline processes and simplify operational tasks. This integrated approach to solving business challenges ensures seamless interactions and delivers valuable insights to SMBs, reinforcing Sage’s position as a leader in the industry.

“Smart Software helps our customers by delivering insightful business analytics for inventory modeling and forecasting that drive ordering and replenishment in the latest version of Sage. With Smart IP&O, our customers gain a means to shape inventory strategy to align with the business objectives while empowering their planning teams to reduce inventory and improve service,” says   Regina Crowshaw, Director of ISV Strategy, Sales, and Programs at Sage.

“Sage drives innovation and fosters business growth by delivering insightful solutions designed to enable organizations to scale and succeed. By leveraging the capabilities of Smart’s field-proven demand forecasting and inventory planning solutions, Sage is poised to supply the necessary expertise to assess needs, establish objectives, and craft the underlying business strategies key for ensuring widespread adoption and deriving maximum benefit.  We look ahead to what we can accomplish together, and we look forward to our joint success”, says Greg Hartunian, President and CEO at Smart Software.

About Smart Software, Inc.

Founded in 1981, Smart Software, Inc. is a leader in providing businesses with enterprise-wide demand forecasting, planning, and inventory optimization solutions.  Smart Software’s demand forecasting and inventory optimization solutions have helped thousands of users worldwide, including customers such as Disney, Hitachi, Arizona Public Service, and Ameren. Smart’s Inventory Planning & Optimization Platform, Smart IP&O, provides demand planners the tools to handle sales seasonality, promotions, new and aging products, multi-dimensional hierarchies, and intermittently demanded service parts and capital goods items. It also provides inventory managers with accurate estimates of the optimal inventory and safety stock required to meet future orders and achieve desired service levels.  Smart Software is headquartered in Belmont, Massachusetts, and our website is www.smartcorp.com.

About Sage Corporation

Sage exists to knock down barriers so everyone can thrive, starting with the millions of Small and Mid-Sized Businesses served by us, our partners, and accountants. Customers trust our finance, HR, and payroll software to make work and money flow. By digitizing business processes and relationships with customers, suppliers, employees, banks, and governments, our digital network connects SMBs, removing friction and delivering insights. Knocking down barriers also means we use our time, technology, and experience to tackle digital inequality, economic inequality and the climate crisis.


For more information, please contact Smart Software, Inc., Four Hill Road, Belmont, MA 02478.
Phone: 1-800-SMART-99 (800-762-7899); FAX: 1-617-489-2748; E-mail: info@smartcorp.com

 

 

Head to Head: Which Service Parts Inventory Policy is Best?

Our customers have usually settled into one way to manage their service parts inventory. The professor in me would like to think that the chosen inventory policy was a reasoned choice among considered alternatives, but more likely it just sort of happened. Maybe the inventory honcho from long ago had a favorite and that choice stuck. Maybe somebody used an EAM or ERP system that offered only one choice. Perhaps there were some guesses made, based on the conditions at the time.

The Competitors

Too seldom, businesses make these choices in haphazard ways. But modern service parts planning software lets you be more systematic about your choices. This post demonstrates that proposition by making objective comparisons among three popular inventory policies:  Order Up To, Reorder Point/Order Quantity, and Min/Max.  I discussed each of these policies in this video blog.

  • Order Up To. This is a periodic review policy where every T days, on-hand inventory is tallied and an order of random size is placed to bring the stock level back up to S units.
  • Q, R or Reorder Point/Order Quantity. Q, R is a continuous review policy where every day, inventory is tallied. If there are Q or fewer units on hand, an order of fixed size is placed for R more units.
  • Min, Max is another continuous review policy where every day, inventory is tallied. If there are Min or fewer units on hand, an order is placed to bring the stock level back up to Max units.

Inventory theory says these choices are listed in increasing order of effectiveness. The first option, Order Up To, is clearly the simplest and cheapest to implement, but it closes its eyes to what’s going on for long periods of time.  Imposing a specified passage of time in between orders makes it, in theory, less flexible. In contrast, the two continuous review options keep an eye on what’s happening all the time, so they can react to potential stockouts quicker. The Min/Max option is, in theory, more flexible than the option that uses a fixed reorder quantity because the size of the order dynamically changes to accommodate the demand.

That’s the theory. This post examines evidence from head-to-head comparisons to check the theory and put concrete numbers on the relative performance of the three policies.

The Meaning of “Best”

How should we keep score in this tournament? If you are a regular reader of this Smart Forecaster blog, you know that the core of inventory planning is a tug-of-war between two opposing objectives: keeping inventory lean vs keeping item availability metrics such as service level high.

To simplify things, we will compute “one number to rule them all”: the average operating cost. The winning policy will be the one with the lowest average.

This average is the sum of three components: the cost of holding inventory (“holding cost”), the cost of ordering replenishment units (“ordering cost”) and the cost of losing a sale (“shortage cost”). To make things concrete, we used the following assumptions:

  • Each service part is valued at $1,000.
  • Annual holding cost is 10% of item value, or $100 per year per unit.
  • Processing each replenishment order costs $20 per order.
  • Each unit demanded but not provided costs the value of the part, $1,000.

For simplicity, we will refer to the average operating cost as simply “the cost”.

Of course, the lowest average cost can be achieved by getting out of the business. So the competition required a performance constraint on item availability: Each option had to achieve a fill rate of at least 99%.

The Alternatives Duke it Out

A key element of context is whether stockouts result in losses or backorders. Assuming that the service part in question is critical, we assumed that unfilled orders are lost, which means that a competitor fills the order. In an MRO environment, this will mean additional downtime due to stockout.

To compare the alternatives, we used our predictive modeling engine to run a large number of Monte Carlo simulations.  Each simulation involved specifying the parameter values of each policy (e.g., Min and Max values), generating a demand scenario, feeding that into the logic of the policy, and measuring the resulting cost averaged over 365 days of operation. Repeating this process 1,000 times and averaging the 1,000 resulting costs gave the final result for each policy.  

To make the comparison fair, each alternative had to be designed for its best performance. So we searched the “design space” of each policy to find the design with the lowest cost. This required repeating the process described in the previous paragraph for many pairs of parameter values and identifying the pair yielding the lost average annual operating cost.

Using the algorithms in Smart Inventory Optimization (SIOTM) we made head-to-head-to-head comparisons under the following assumptions about demand and supply:

  • Item demand was assumed to be intermittent and highly variable but relatively simple in that there was neither trend nor seasonality, as is often true for service parts. Daily mean demand was 5 units with a large standard deviation of 13 units. Figure 1 shows a sample of one year’s demand. We have chosen a very challenging demand pattern, in which some days have 10 to even 20 times the average demand.

Daily part demand was assumed to be intermittent and very spikey.

Figure 1: Daily part demand was assumed to be intermittent and very spikey.

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  • Suppliers’ replenishment lead times were 14 days 75% of the time and 21 days otherwise. This reflects the fact that there is always uncertainty in the supply chain.

 

And the Winner Is…

Was the theory right? Kinda’ sorta’.

Table 1 shows the results of the simulation experiments. For each of the three competing policies, it shows the average annual operating cost, the margin of error (technically, an approximate 95% confidence interval for the mean cost), and the apparent best choices for parameter values.

Results of the simulated comparisons

Table 1: Results of the simulated comparisons

For example, the average cost for the (T,S) policy when T is fixed at 30 days was $41,680. But the Plus/Minus implies that the results are compatible with a “true” cost (i.e., the estimate from an infinite number of simulations) of anywhere between $39,890 and $43,650. The reason there is so much statistical uncertainty is the extremely spikey nature of demand in this example.

Table 1 says that, in this example, the three policies fall in line with expectations. However, more useful conclusions would be:

  1. The three policies are remarkably similar in average cost. By clever choice of parameter values, one can get good results out of any of the three policies.
  2. Not shown in Table 1, but clear from the detailed simulation results, is that poor choices for parameter values can be disastrous for any policy.
  3. It is worth noting that the periodic review (T,S) policy was not allowed to optimize over possible values of T. We fixed T at 30 to mimic what is common in practice, but those who use the periodic review policy should consider other review periods. An additional experiment fixed the review period at T = 7 days. The average cost in this scenario was minimized at $36,551 ± $1,668 with S = 343. This result is better than that using T = 30 days.
  4. We should be careful about over-generalizing these results. They depend on the assumed values of the three cost parameters (holding, ordering and shortage) and the character of the demand process.
  5. It is possible to run experiments like those shown here automatically in Smart Inventory Optimization. This means that you too would be able to explore design choices in a rigorous way.

 

 

 

The Forecasting Process for Decision-Makers

In almost every business and industry, decision-makers need reliable forecasts of critical variables, such as sales, revenues, product demand, inventory levels, market share, expenses, and industry trends.

Many kinds of people make these forecasts. Some are sophisticated technical analysts, such as business economists and statisticians. Many others regard forecasting as an important part of their overall work: general managers, production planners, inventory control specialists, financial analysts, strategic planners, market researchers, and product and sales managers. Still, others seldom think of themselves as forecasters but often have to make forecasts on an intuitive, judgmental basis.

Because of the way we designed Smart Demand Planner, it has something to offer all types of forecasters. This design grows out of several observations about the forecasting process. Because we designed Smart Demand Planner with these observations in mind, we believe it has a style and content uniquely suited for turning your browser into an effective forecasting and planning tool:

Forecasting is an art that requires a mix of professional judgment and objective, statistical analysis.

It is often effective to begin with an objective statistical forecast that automatically accounts for trends, seasonality, and other patterns.  Then, apply adjustments or forecast overrides based on your business judgment. Smart Demand Planner makes it easy to execute graphical and tabular adjustments to statistical forecasts.

The forecasting process is usually iterative.

You will likely decide to make several refinements of your initial forecast before you are satisfied. You may want to exclude older historical data that you find to no longer be relevant.  You could apply different weights to the forecast model that put varying emphases on the most recent data. You could apply trend dampening to increase or decrease aggressively trending statistical forecasts.  You could allow the Machine Learning models to fine-tune the forecast selection for you and select the winning model automatically.  Smart Demand Planner’s processing speed gives you plenty of time to make several passes and saves multiple versions of the forecasts as “snapshots” so you can compare forecast accuracy later.

Forecasting requires graphical support.

The patterns evident in data can be seen by a discerning eye. The credibility of your forecasts will often depend heavily on graphical comparisons other business stakeholders make when they assess the historical data and forecasts. Smart Demand Planner provides graphical displays of forecasts, history, and forecast vs. actuals reporting.

Forecasts are never exactly correct.

Because some error always creeps into even the best forecasting process, one of the most useful supplements to a forecast is an honest estimate of its margin of error.

Smart Demand Planner presents both graphical and tabular summaries of forecast accuracy based on the acid test of predicting data held back from development of the forecasting model. 

Forecast intervals or confidence intervals are also very useful.  They detail the likely range of possible demand that is expected to occur.  For example, if actual demand falls outside of the 90% confidence interval more than 10% of the time then there is reason to investigate further.  

Forecasting requires a match of method to data.

One of the major technical tasks in forecasting is to match the choice of forecasting technique to the nature of the data. Features of a data series like trend, seasonality or abrupt shifts in level suggest certain techniques instead of others.

Smart Demand Planner’ Automatic forecasting feature makes this match quickly, accurately and automatically.

Forecasting is often a part of a larger process of planning or control.

For example, forecasting can be a powerful complement to spreadsheet-based financial analysis, extending rows of figures off into the future. In addition, accurate sales and product demand forecasts are fundamental inputs to a manufacturer’s production planning and inventory control processes. An objective statistical forecast of future sales will always help identify when the budget (or sales plan) may be too unrealistic. Gap analysis enables the business to take corrective action to their demand and marketing plans to ensure they do not miss the budgeted plan.

Forecasts need to be integrated into ERP systems
Smart Demand Planner can quickly and easily transfer its results to other applications, such as spreadsheets, databases and planning systems including ERP applications.  Users are able to export forecasts in a variety of file formats either via download or to secure FTP file locations.  Smart Demand Planner includes API based integrations to a variety of ERP and EAM systems including Epicor Kinetic and Epicor Prophet 21, Sage X3 and Sage 300, Oracle NetSuite, and each of Microsoft’s Dynamics 365 ERP systems. API based integrations enable customers to push forecast results directly back to the ERP system on demand.

The result is more efficient sales planning, budgeting, production scheduling, ordering, and inventory planning.

 

 

 

 

Procon Pumps Uses Smart Demand Planner to Keep Business Flowing

Introduction:
Procon, an industry leading pump manufacturer, uses Smart IP&O’s demand planning and inventory optimization modules from Smart Software to make sure they have the products their customers need, when they need them.  You might not have heard of their products, but if you’ve ever eaten at McDonalds or sipped a coffee at Starbucks, you have been served by Procon.  Procon’s broad portfolio of over 7,000 SKUs is supplied to more than 70 countries worldwide through their direct sales channel and an extensive distributor network.  Procon operates manufacturing facilities in the US, Mexico, Ireland, and through a licensed manufacturing partner in Japan.  We spoke with Procon’s Shankar Suman, Director of Sales, and Emer Horan, Global Supply Chain Manager, to learn more.

The Challenge
If Procon cannot ship a required product, their customers cannot ship theirs.  Accurate forecasting is a key driver of supply chain success and customer satisfaction. Procon’s monthly planning establishes the consensus demand plan that drives procurement, production, and stocking policies.  But they found they had a gap between sales and procurement, which historically led to missed deliveries and excess inventory.  What Procon needed was a robust demand forecasting and inventory optimization tool that was easy to use, enabled collaborative planning with their sales team and partners, and integrated with their  ERP system to drive procurement and production planning.

The Solution:
They found this in Smart IP&O,  web-based platform for statistical forecasting, demand planning, and inventory optimization.

  • Shankar Suman cited a broad mix of capabilities that convinced them to utilize Smart. Chief among them were:
  •   Smart Demand Planner supports the easy, orchestrated flow of information that yields an accurate consensus plan.  Presenting performance history and statistical forecast by product, territory, and partner, SDP provide the sales team with perspective that they can complement – adjusting for expected opportunities or demand shifts.
  • Forecast accuracy. Smart is an industry leader in statistical analytics, leveraging innovations developed over its forty-plus year history.  This combined with robust forecast vs. actuals analysis helps Procon continually improve the quality of their forecasts.
  • Transparent connectivity with Procon’s enterprise software, Epicor Kinetic. Daily sales and shipment data are automatically pulled into the Smart platform, fueling Smart’s forecasting engine, and results are easily pushed back to the ERP (MRP) via an API based integration to drive ordering and production planning.

Results:
Emer Horan explained how this plays out over the course of each month.   Emer provides forecasts for each of their five sales managers, they meet to compare statistical and sales forecasts, and agree on a revised 12-month consensus plan.  The sales managers have a good sense for the top accounts that represent 80% of revenue, often including direct input from customers themselves, and the statistical forecast fills in the gaps.  Next month they use the forecast vs. actual analytics to help improve accuracy, then repeat the process.

“Our sales team is incentivized to maintain and improve sales forecast accuracy,” said Emer, “and we have the tools to help them succeed.  This not only ensures optimal inventory levels but also contributes to improved on-time delivery and higher customer satisfaction.”

“Our journey with Smart Software has been quite remarkable,” added Shankar. “We began with an initial idea of the functionality and interface, and it has continually evolved from there. The Smart team has shown tremendous support and patience with our scope changes, delivering the product exactly the way we needed and wanted it.  We have been using Smart for over three years now, and this journey is ongoing. We continue to receive excellent support from the Smart team and truly enjoy working with them.”