In order to correctly adjust the order point, users need to know what is the inventory turnover of each goods. If it is too low, company may want to lower the quantity or even return extra stock level to the supplier.
Proposal
A new report is added to the “Inventory & Stock” which display for each goods the quantity sold (the quantity moved out to customers minus the quantity returned by customers), the average stock level and the turnover (as quantity sold / average stock level) over a period defined in the context and for a warehouse.
I’m wondering if the quantity is enought to have proper reporting.
Having 1.000 units of some product valued as 0.01€ its no more important than having 50 units of a product valued at 100€.
For me it make sense to include for each quantity metric include also the goods value.
For me this is making too much assumption about the storage cost.
We do not know what are the criteria that users will use to evaluate the turnover. They may even vary per product and/or warehouse.
Sorry but I did not make any assumption. Just mentioned that the value of the product may have an impact in the inventory turnover as quantities can not just represent the value of a stock.
Inventory turnover is a criteria that is used to compare the performance of similar companies and can be computed using accounting values. See:
Do not understand what you mean with this sentence. No mather how if it varies the product always have a valuation.
I see no explanation why the cost of the goods is important for this topic.
The inventory turnover provides information about how the stock buffer behaves in the warehouse. Optimizing this buffers is related to the storage cost and not the product cost.
But of course when adapting the order point quantities, users must be careful about the cost of the goods but it is another matter.
The quantity may give the feeling that a product has a lot of impact on the turnover while it is not really so much important because its value of the goods is small compared to its quantity moved.
For me you are just assuming one cost may be more relevant than the other which may not be true for the company. The product cost has a direct impact on the company cash flow and may produce the need to ask for credits.
Here is a first draft Add stock inventory reporting (!2588) · Merge requests · Tryton / Tryton · GitLab
I found I have a better way and faster with this design to calculate the inventory history. Thus I think it will replace the *product_quantities_warehouse* models once I define a simple stock.reporting.inventory and stock.reporting.inventory.move models.
When a company looks at what is the size of an issue with the products in their warehouse (do they have too much stock?), they always look at the value first, not the number of units.
For me, the most important criteria are: stock valuation, units stored, volume stored.
I agree with others units and valuation arguments. But as nobody pointed out volume criteria, I think it’s important to know what is making your warehouse space full in relation to units or valuation.
I want to also point out a quick demo using TreeMap visualization over the same data on the 3 main with related products so you can see in a quick view the other 2 criteria. I think this type of view is important for this scenario.
The merge request contains now the inventory turnover report but also an inventory, inventory moves and inventory daily reports.
I tested on a database with ~30k stock moves and 2k products, the turnover report for 1 year is calculated in about 50ms (on my laptop). The query plan is pretty good and can use many indexes.
I plan to make a second commit that will remove all the *QuantitiesByWarehouse* models and include the cost value to the Inventory report.
I guess you propose to deprecate them and replace its model by the new daily model right?
Do not forget to update the stock_quantity_issue which uses such models to generate the issues.