Warehouse Performance Measurement

God, grant me serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference. Reinhold Niebuhr

Performance foundations

01

🧠 Learning objectives

  • Understand the role of KPIs in measuring warehouse performance and driving improvements.
  • Learn benchmarking techniques to evaluate and compare warehouse performance.
  • Explore methods for selecting and implementing effective KPIs in warehouse operations.

What is a KPI?

  • A KPI is a performance measurement tool for an organization or specific activity.
  • Importance: It reflects the success of activities, assesses key objectives, monitors progress, and evaluates efficiency/productivity.
  • Challenges: Data collection, selecting the right metrics, and ensuring consistency.

A general warehouse model

Performance is measured in terms of ratios of output and input factors (De Koster 2012).

Inputs of labor, space, equipment, inventory, and practices enter a warehouse transformation and produce piece, case, and pallet lines, returns handling, value-added services, storage, and accumulation.

Figure 1: Example of input and output variables for a general warehouse model by Johnson and McGinnis (2010).

Metrics → Decisions

  • Typical OR view: start by defining an objective function and constraints.
  • Real-world: performance is multi-dimensional, so single-objective models miss trade-offs. Options:
    • Use multi-objective optimization techniques (e.g., genetic algorithms, Pareto optimization, weighted sum approaches).
    • Rank objectives by importance (KPI pyramid).

Three ways a metric enters a decision model

  1. Objectives to minimize/maximize (e.g., cost, productivity, service).
  2. Limits (constraints) such as:
    • service level \(\geq\) threshold
    • damage \(\leq\) cap
    • labor/space/equipment capacities
  3. Targets (setpoints) manage deviation from desired values, for example:
    • Storage utilization band (70–90%).
    • Storage utilization of 85%.

Choose a decision model that matches the metric

  • Single Criterion Decision Making: Optimize one objective function subject to constraints.
  • Multi-Criteria Decision Making: Simultaneously optimize multiple conflicting objectives. Common approaches include:
    • AHP (Analytic Hierarchy Process): Pairwise comparisons to derive weights and rank alternatives (Saaty 1980).
    • Goal Programming: Minimizes deviations from set goals subject to constraints (Charnes et al. 1955).

Efficiency and trade-off methods answer different questions

  • Data Envelopment Analysis (DEA): Nonparametric efficiency measurement of decision-making units (see Abraham Charnes et al. 1978).
  • Multi-objective Optimization: Pareto-based search for trade-offs (e.g., Deb et al. 2002).
  • Best-Worst Method (BWM): Criteria weights from comparisons of best against others and others against worst (see Rezaei 2015). It requires fewer comparisons than AHP and can reduce the burden on decision makers.

Benchmarking warehouse performance

02

Benchmarking

  • Benchmarking is the process of comparing one’s products, business processes, or strategies to those of the most successful firms in the same or other industries (Park 2012).
  • Common dimensions measured: quality, time, and cost.
  • Typically provides a single efficiency score for performance comparison.

Internal vs. external benchmarks

  • Internal benchmarks: Evaluate performance within your warehouse by comparing similar entities such as sites, shifts, zones, or teams to identify top practices and performance gaps.
    • Project comparison: Assess improvements by analyzing pre/post KPI changes; be cautious of inconsistent KPI definitions, lack of standardization, and overlapping effects.
    • Historical comparison: Track performance trends over months or years, accounting for disruptions or changes in scope.
  • External benchmarks: Measure performance against industry norms or competitors (e.g., top-tier metrics, market studies). Pay attention to warehouse type/scale, confidentiality constraints, and interpretation challenges.
    • Sources: Industry reports, trade associations, peer panels, 3PL/client councils, MHE/WMS vendor benchmarks, analyst/consulting reports.

External benchmarks require comparable operations

When benchmarking externally, it is crucial to ensure that comparisons are meaningful. Demirkran and Ozturkoglu (2022) highlight several factors that can significantly influence KPIs:

  • Warehouse type: Import, regional, grocery, wholesale, local, omni-channel, e-commerce, etc.
  • Industry: Retail, wholesale distribution, 3PL (third-party logistics), manufacturing, pharmaceutical, medical device, utilities/government, etc.
  • Handling unit: Broken case, full case, full pallet picking.
  • Geography: Developed vs. developing countries, regional differences.

Warehouse performance metrics in literature and practice

  • Literature reviews:
    • Staudt et al. (2015) extracted 38 direct and 8 indirect measures across time, quality, cost, and productivity.
    • Chen et al. (2017) linked KPIs, critical success factors, and capabilities, identifying eight KPIs from four case studies.

Warehouse performance metrics in industry

  • Industry benchmarking:
    • Hackman et al. (2001) benchmarked 57 warehouses using DEA, finding efficiency negatively associated with size and higher automation levels.
    • Johnson and McGinnis (2010) reported initial multi-site benchmarking results using an internet-based DEA tool for warehouses (iDEAs-W).
    • WERC’s yearly DC Measures reports (e.g., Tillman et al. 2022) show metric priorities shifting over time across DCs.

Industry vs. Academia?

Demirkran and Ozturkoglu (2022) highlight that while previous studies have provided extensive lists of warehouse performance measures, selecting a concise set of metrics that are valuable, balanced (financial and non-financial), goal-oriented, and aligned with operational priorities remains a critical challenge. This requires considering both industry and academic perspectives.

Selecting and improving KPIs

03

Cycle time metrics

  • A cycle time is the total elapsed time to complete a process from start to finish (Tillman et al. 2022, 9–11).
  • Common warehouse cycle times include:
    • (Total) Order Cycle Time (OCT): Time from customer order to delivery.
    • Internal Order Cycle Time: Time from order release to shipment.
    • Dock-to-Stock Cycle Time: Time from receiving dock to storage location.
    • Pick Cycle Time: Time taken to pick items for an order.
    • Putaway Cycle Time: Time taken to store received items.
Order-cycle milestones from order placement to delivery: release, pick start, pick completion, packing completion, and shipment loading; intervals are not to scale.

Figure 2: Order Cycle Time (OCT) from customer order to delivery. Milestone spacing is illustrative rather than proportional to elapsed time.

What KPIs can be measured from WMS data?

Diamantini et al. (2014) distinguish between goal-driven and data-driven KPI selection methods.

  • Goal-driven: Start from management goals, map to fields of interest, then select KPIs that indicate progress toward that goal.
  • Data-driven: Select KPIs primarily from data availability and statistical signal in the operational data, without first anchoring to explicit business goals.

See applicability in Franken (2025).

How to close the performance gaps?

Warehousing & Fulfillment Process Benchmark & Best Practices Guide (2007) provides a practical framework to identify and implement best practices in warehousing operations:

  1. Localize gaps with a structured self-assessment by process group.
  2. Quantify the performance gap with benchmarked KPI bands.
  3. Diagnose root causes using process benchmarks and best-practice attributes.
  4. Select improvement levers that line up with the measured gap.
  5. Prioritize initiatives by impact, effort, and statistical signal.

Warehouse assessment tools

04

A single tour can structure a warehouse assessment

De Koster (2012) presents a quick and structured method to assess a warehouse’s performance across 11 key areas. Each area is rated on a six-category scale (Poor=1, Below Average=3, Average=5, Above Average=7, Excellent=9, Best in Class=11), enabling a comprehensive evaluation of:

  1. Customer satisfaction
  2. Cleanliness, environment, ergonomics, safety, hygiene (HACCP)
  3. Use of space, building & technical installations
  4. Condition & maintenance of material handling equipment (MHE)
  5. Teamwork, management & motivation
  6. Storage systems & inventory management
  7. Order-picking systems & strategies
  8. Supply-chain coordination
  9. Level & use of IT
  10. Commitment to quality
  11. Managing efficiency and flexibility

WERC benchmarks KPIs by performance quintile

Tillman et al. (2022) present quintile rankings (Major Opportunity, Disadvantage, Typical, Advantage, Best-in-Class) for common warehouse KPIs, grouped by family:

  • Customer Metrics: On-time Shipments, Total Order Cycle Time, Internal Order Cycle Time, Backorders as a Percentage of Total Lines
  • Operations Metrics:
    • Inbound: Dock-to-Stock Cycle Time (in Hours), Lines Received and Put Away per Hour, Percent of Supplier Orders Received with Correct Documents, Percent of Supplier Orders Received Damage Free, On-time Receipts — Supplier
    • Outbound: Fill Rate–Case, Order Fill Rate—Case, Lines Picked and Shipped per Person Hour, Orders Picked and Shipped per Person Hour, On-time Ready to Ship.

WERC measures: financial, capacity, and workforce

  • Financial Metrics: Distribution Cost as a Percent of Sales, Distribution Cost per Unit Shipped, Distribution Cost as Percent of COGS, Days on Hand—Finished Goods
  • Capacity/Quality Metrics: Average Warehouse Capacity Used, Peak Warehouse Capacity Used, Honeycomb Percentage, Cube Utilization, Inventory Count Accuracy (Percent by Location), Order-picking Accuracy (Percent by Order)
  • Employee Metrics: Annual Workforce Turnover, Overtime Hours to Total Hours, Part-time Workforce to Total Workforce, Contract Employees to Total Workforce, Unplanned Absence Percentage, Cross Trained Percentage
  • Perfect Order Index Metrics: Percent of Orders with On-time Delivery, Shipped Complete per Customer Order, Shipped Damage Free (Outbound), Correct Documentation (ASM Invoice, etc.)
  • Cash to Cash Metrics: Inventory Days of Supply, Average Days Payable, Average Days of Sales Outstanding

Reported WERC metrics: ranks 1–6

Table 1: WERC metrics ranked 1–6 in 2022 (from Tillman et al. 2022).
Rank Metric Category
1 Average Warehouse Capacity Used Capacity
2 Order-picking Accuracy (Percent by Order) Quality
3 On-time Shipments Customer
4 On-time Ready to Ship Outbound Operations
5 Peak Warehouse Capacity Used Capacity
6 Dock-to-Stock Cycle Time, in Hours Inbound Operations

Reported WERC metrics: ranks 7–12

Table 2: WERC metrics ranked 7–12 in 2022 (from Tillman et al. 2022).
Rank Metric Category
7 Supplier Orders Received Damage Free Inbound Operations
8 Orders with On-time Delivery POI*/Customer
9 Order Fill Rate Outbound Operations
10 Shipped Damage Free (Outbound) POI/Customer
11 Fill Rate—Line Outbound Operations
12 Shipped Complete per Customer Order POI/Customer

References

Sources cited in this deck

Bartholdi, J. J., and S. T. Hackman. 2019. Warehouse & Distribution Science. 0.98.1 ed. Georgia Institute of Technology. https://www.warehouse-science.com/book/editions/wh-sci-0.98.1.pdf.
Charnes, Abraham, William W. Cooper, and Robert O. Ferguson. 1955. “Optimal Estimation of Executive Compensation by Linear Programming.” Management Science 1 (2): 138–51. https://doi.org/10.1287/mnsc.1.2.138.
Charnes, Abraham, William W. Cooper, and Edward Rhodes. 1978. “Measuring the Efficiency of Decision Making Units.” European Journal of Operational Research 2 (6): 429–44. https://doi.org/10.1016/0377-2217(78)90138-8.
Charnes, A., W. W. Cooper, and E. Rhodes. 1978. “Measuring the Efficiency of Decision Making Units.” European Journal of Operational Research 2 (6): 429–44. https://doi.org/10.1016/0377-2217(78)90138-8.
Chen, Ping-Shun, Chun-Ying Huang, Chang-Chun Yu, and Chi-Chuan Hung. 2017. “The Examination of Key Performance Indicators of Warehouse Operation Systems Based on Detailed Case Studies.” Journal of Information and Optimization Sciences 38 (2): 367–89. https://doi.org/10.1080/02522667.2016.1224465.
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Deb, Kalyanmoy, Amrit Pratap, Sameer Agarwal, and T. Meyarivan. 2002. “A Fast and Elitist Multiobjective Genetic Algorithm: NSGA-II.” IEEE Transactions on Evolutionary Computation 6 (2): 182–97. https://doi.org/10.1109/4235.996017.
Demirkran, Yeliz, and Omer Ozturkoglu. 2022. “Key Performance Measures and Digital-Era Technologies in Warehouses.” Operations and Supply Chain Management: An International Journal 15 (2): 193–204. https://doi.org/10.31387/oscm0490340.
Diamantini, Claudia, Laura Genga, Domenico Potena, and Emanuele Storti. 2014. “A Semi-Automatic Methodology for the Design of Performance Monitoring Systems.” SEBD, 111–22. https://www.academia.edu/download/34320862/sebd2014.pdf.
Franken, D. G. M. 2025. “Developing a Hybrid Product Selection Method Based on KPI Selection Methods for Selecting Suitable BI Products Containing KPIs : A Case Study in the Field of Warehousing.” Thesis, University of Twente. https://purl.utwente.nl/essays/106789.
Hackman, Steven T., Edward H. Frazelle, Paul M. Griffin, Susan O. Griffin, and Dimitra A. Vlasta. 2001. “Benchmarking Warehousing and Distribution Operations: An Input-Output Approach.” Journal of Productivity Analysis 16 (1): 79–100. https://doi.org/10.1023/A:1011155320454.
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Rezaei, Jafar. 2015. “Best-Worst Multi-Criteria Decision-Making Method.” Omega 53: 49–57. https://doi.org/10.1016/j.omega.2014.11.009.
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Staudt, Francielly Hedler, Gülgün Alpan, Maria Di Mascolo, and Carlos M. Taboada Rodriguez. 2015. “Warehouse Performance Measurement: A Literature Review.” International Journal of Production Research, ahead of print. https://doi.org/10.1080/00207543.2015.1034666.
Tillman, Joseph, Karl B. Manrodt, and Donnie F. Williams Jr. 2022. 2022 DC Measures: Annual Survey and Report on Industry Metrics. Warehousing Education and Research Council. https://werc.org/metrics.
Warehousing & Fulfillment Process Benchmark & Best Practices Guide. 2007. Warehousing Education and Research Council.