A picking task appears on the list at 08:02, and a warehouse worker opens it at 08:07. If they confirm the pick at 08:15, that gives you five minutes in the queue and eight minutes from opening to completion. Which times you subtract determines what you can say about picking in your logistics thesis.
Start with one picking task. Find it in the export and write down all three times in order. Next to each time, note what was happening on the warehouse floor. If you are studying the customer's order from acceptance to delivery, look for the times when the warehouse accepted the order and when the customer received it.
What happens between opening and completing a task?
WMS stands for warehouse management system. Ask someone who knows the setup to walk you through one task. The “start” field might record when a worker opens the task on their terminal or when they scan the first item. A clock that starts at the first scan leaves out the walk to the shelf. Also check whether the system records when the event happens or when the terminal sends it. If the terminal syncs later, those times may differ.
In the 08:07 example, the clock starts when the task is opened and stops when the worker confirms that they have picked every item. Those eight minutes might include walking to the shelves, scanning and pausing to check why an item is missing. To measure active working time separately, you would need a more detailed log or direct observation. Głodowska and Świderski break picking time down into activities such as travel and retrieval. The Lean Enterprise Institute makes a related distinction between time through the process and the operator's cycle time.
- What are you counting? In this example, each picking task has its own result. When a warehouse picks in waves, several tasks may belong to one order or a single task may cover items for several customers. Check how they are linked before summarising times by order.
- Which tasks are in the study? Choose the event that makes a task eligible, such as release between 08:00 and 09:00. Decide how late you will look for completion records. Put both decisions in your methods section.
- Do the times add up? Check full dates and the time zone, especially for night shifts. If an end time comes before the start, look at the original record. For duplicates and reopened tasks, ask someone who knows the process which events belong to the same attempt.
Six tasks in the log. How many can you time?
Take a fictional warehouse where six tasks were released in one zone between 08:00 and 09:00. We stop observing at 09:00. All times are from the same day and use the warehouse's local time. Each task relates to one order. In this example, none of the tasks are split into parallel jobs or reopened.
These tasks have both times
- A. The task was released at 08:02, opened at 08:07 and confirmed complete at 08:15. Eight minutes passed from opening to completion. From release to completion, it was 13 minutes.
- B. Released at 08:04, opened at 08:12, confirmed at 08:26. The task took 14 minutes from opening to completion.
- C. Released at 08:10, opened at 08:12, confirmed at 08:42. The task took 30 minutes from opening to completion.
These tasks each need an explanation
- D. The log shows when the task was completed, but the opening time is missing. You can calculate the time from release to completion. Record it separately if that interval is part of your study.
- E. The worker had started picking and the task was still open at 09:00. You know how many minutes had passed when observation ended. You need the later confirmation to calculate the full time.
- F. The task was cancelled before picking began. Record cancellation separately from missing times.
Put the times in order and you get 8, 14 and 30 minutes. The middle value, or median, is 14 minutes. The mean is (8 + 14 + 30) / 3, rounded to 17.3 minutes. Both figures describe three of the six tasks. Entering zeros for missing times would pull the mean down. If you later recover the opening time for D, record where it came from and apply the same calculation rule. For E, you can report a result outside the original window separately and state when you stopped observing.
What goes in the methods and results sections?
In the methods section, give the source of the data, what you counted and exactly when the clock started and stopped. In the results, report the figures and how many tasks they cover. The two paragraphs below show how. For your own thesis at a university in Poland, use the date, zone and event descriptions from the warehouse you studied.
Method. From the WMS log, we selected picking tasks released in one warehouse zone from 08:00 inclusive to 09:00 exclusive. For each task, we subtracted the time it was opened on the terminal from the time it was confirmed complete. We report the difference in minutes. We included tasks with both times recorded by 09:00.
Result. We could calculate a time for three of the six tasks released. The median was 14 minutes and the mean was 17.3 minutes. Of the other three tasks, one had a missing opening time, one was still in progress and one had been cancelled. Longer tasks may be more likely to remain open when observation ends, so these figures describe only the tasks with complete records.
If you compare two zones, check whether “start” means the same thing in both. For each zone, give the number of tasks released, the number you could time and the reasons for excluding any tasks. Check the number of order lines and the types of goods as well. Jakubiak and Michalski use simulation to compare zone layouts and picking routes. Augustyn Lorenc describes picking methods and shows how a simulation can account for travel, retrieving items and related activities. A log like the one in this example shows differences in duration. You need more information on how the tasks were carried out to work out what caused those differences.
What should you check before handing in the chapter?
- Read the name of the measure and find the two times you subtract in the methods section.
- Check that the counts of timed, incomplete, open and cancelled tasks add up. State when you stopped tracking their status.
- Compare the units and counts in the chapter and in your figure captions.
- Make sure you have permission to use the data and illustrations in the thesis.
If you also measure queue time, give it a separate definition with its own start and end. Find more examples of how to define a measure in the guide to choosing measures for your thesis.
Questions about methods and study limitations
Can you check an already written methodological chapter?
Yes. I can analyse its structure, the link between the objectives and research questions, and the consistency of the descriptions of the methods and research instrument. Include your supervisor's comments and the questionnaire or interview guide itself so that I can assess the whole, rather than the description alone.
How can I connect a limitation to its effect on the conclusions?
Identify a specific feature of the procedure, the finding or claim it affects, and the consequence. Then explain what you actually did to address it and what remains uncertain. A generic list mentioning sample size and time pressure is not enough.
Sources
- Głodowska, K., Świderski, A. (2019). Optymalizacja procesu kompletacji. Prace Naukowe Politechniki Warszawskiej. Transport, 127, 15-24.
- Lorenc, A. (2016). Wpływ metody klasyfikacji produktów na efektywność transportu wewnątrzmagazynowego. Cracow University of Technology, doctoral dissertation, chapters 3-4. University repository, record 26201.
- Jakubiak, M., and Michalski, P. (2015). Wpływ procesu komisjonowania zamówień w węźle logistycznym na dostępność produktów w łańcuchu dostaw. Logistyka, 2/2015, 284-295.
- Lean Enterprise Institute. Value Stream Mapping, Lean Lexicon, “Process data boxes” under “Value-Stream Map Zones”. Accessed 9 November 2026.
Discuss a measurement for your logistics thesis
Tell us what you want to find out from the log. If you can, share an anonymised extract, your university guidelines and a draft paragraph on the method or results. That gives us a clear place to start.
