Decision Making
Stock Ordering Task
Also called: newsvendor task, newsvendor problem, newsvendor experiment, pull-to-center effect, demand chasing
Measure stock ordering under uncertain demand: order boxes, see sales and waste, and compare orders with average demand and the previous round.
5-8 minUntimed
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Try it here first, with no account.
- Papers, 2021 to 2025
- 50
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
Measures how stock orders move toward average demand and follow the previous round. Participants order boxes before demand is revealed, then see sales, waste and points gained or lost. The study sets a high or low profit margin.
Constructs
- Inventory decision making
- Anchoring on mean demand
- Learning from feedback
Research uses
- Behavioral operations research
- Research on decisions under uncertainty
How the paradigm works
The Stock Ordering Task measures ordering under uncertain demand. People choose stock before they know how much will sell. In the newsvendor experiment, orders lean toward mean demand and shift after the demand of the previous round (Schweitzer and Cachon, 2000).
More about the paradigm
This version uses our own boxes, quantities, points and screens. Independent demand is uniform from 0 to 100 inclusive, with mean 50 stated to participants. The standard session has 30 rounds, with 10 to 100 available. The study selects high or low margin and a sale price of 4, 8 or 12 points. Unsold boxes expire, with no salvage value; unfilled demand earns nothing. One worked check with feedback comes first. Every result waits for the participant to continue. There is no time limit.
Scores
- Pull to Mean Demandscore
- Mean order relative to the optimum and mean demand: (mean order - optimum) / (50 - optimum).
- 0 is optimal; 1 is mean demand; values can fall outside 0 to 1
- Demand Chasingscore
- Through-origin slope of consecutive order changes on the preceding demand-minus-order gap; null if all gaps are zero.
- 0 is no adjustment; 1 copies last demand
- Mean Ordercount
- Average number of boxes ordered.
- Informational
- Mean Realized Demandcount
- Average demand revealed in completed rounds.
- Informational
- Expected-Points Optimal Ordercount
- 75 boxes at high margin or 25 at low margin for the stated distribution.
- Fixed comparison for these settings
- Net Pointspoints
- Sales revenue less the cost of every box ordered, summed across completed rounds.
- More points means a higher realized return
- Unsold Boxescount
- Total boxes ordered but not sold.
- Informational
- Missed Salescount
- Total boxes demanded beyond available stock.
- Informational
- Check Correctflag
- 1 for a correct example answer, 0 for an incorrect answer.
- A wrong answer is flagged for review
- Median Choice Timems
- Median confirmation time over choices at or after 100 ms.
- Informational
- Choices Under 100 mscount
- Confirmed orders made less than 100 ms after the screen appeared.
- 0 expected
- Rounds Completedcount
- Number of readable confirmed stock orders in the selected run.
- Fewer than planned is flagged for review
- Planned Roundscount
- Number of rounds set before the session.
- Informational
Use and evidence
50 papers from 2021 to 2025 name this task in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 360 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 7 |
| 2024 | 17 |
| 2023 | 9 |
| 2022 | 7 |
| 2021 | 10 |
| 2020 | 9 |
| 2019 | 5 |
| 2018 | 10 |
| 2017 | 14 |
| 2016 | 15 |
| 2015 | 8 |
| 2014 | 18 |
| 2013 | 7 |
| 2012 | 12 |
| 2011 | 4 |
| 2010 | 4 |
| 2009 | 3 |
| 2008 | 3 |
| 2007 | 0 |
| 2006 | 0 |
| 2005 | 1 |
| 2004 | 0 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 1 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 8
- Registered clinical studies using it as an outcome
- 0
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.39.0, counted 10 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Rounds
- 30 rounds as standard, from 10 to 100. Each starts with no stock. Choose 0 to 100 boxes, then see demand, sales, unsold boxes, missed sales and net points. Results wait for a button press.
- Demand
- Independent uniform whole numbers from 0 to 100 inclusive, with mean 50. Each demand is drawn from the session seed before play and revealed only after the order. Last round’s demand and total points stay visible while ordering.
- Price and cost
- Sale price is 4, 8 or 12 points. High margin costs one quarter of the price; low margin costs three quarters. Unsold stock is lost and missed sales earn nothing. Only points are used.
- Check
- One example with feedback: order 10 boxes when demand is 6. Four are unsold. The feedback explains the net points at the selected price and cost.
- Scores
- Pull to the mean is (mean order minus optimal order) divided by (50 minus optimal order): 0 at the optimum, 1 at mean demand. The expected-points optimum is 75 at high margin or 25 at low margin. Demand chasing is the slope through the origin of the order change on the previous demand-minus-order gap, using consecutive rounds. If all gaps are zero, there is no coefficient.
This is an original points-based version of the newsvendor experiment. Quantities and screens differ from the published task. Compare people with the same settings. Scores describe ordering behavior within the task; no percentile or diagnostic output.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: confirmed stock orders. Constant orders are accepted. An unfinished run or wrong check answer is flagged for review. Choices under 200 ms on at least half the rounds invalidate.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. A constant order can maximize expected points, so repeated quantities are accepted. An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Rounds | 30 | 10 to 100 |
| Profit margin | High (standard) | High (standard), Low |
| Sale price in points | 4 | 4, 8, 12 |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Untimed test: runs on desktops, laptops, tablets and phones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Stock Ordering Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Schweitzer ME, Cachon GP, 2000), with the standard settings (rounds: 30; profit margin: High; sale price in points: 4). The main score was pull to mean demand (mean order relative to the optimum and mean demand: (mean order - optimum) / (50 - optimum)).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Schweitzer, M. E., & Cachon, G. P. (2000). Decision Bias in the Newsvendor Problem with a Known Demand Distribution: Experimental Evidence. Management Science, 46(3), 404-420. https://doi.org/10.1287/mnsc.46.3.404.12070The known-demand newsvendor experiment and ordering toward mean demand and the previous demand.
Source papers
Questions
How long does the Stock Ordering Task take?
About 5 to 8 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Pull to Mean Demand, Demand Chasing, Mean Order, Mean Realized Demand, Expected-Points Optimal Order, Net Points, Unsold Boxes, Missed Sales, Check Correct, Median Choice Time, Choices Under 100 ms, Rounds Completed and Planned Rounds. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Stock Ordering Task used in research?
50 papers from 2021 to 2025 name it in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 360 of 582 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.39.0, counted 10 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Stock Ordering Task have?
In the published research, 0 papers report its test-retest reliability and 0 registered clinical studies use it as an outcome (evidence grade D in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Rounds (10 to 100), profit margin (High (standard), Low) and sale price in points (4, 8, 12). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
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