Why is the amount of the reference product changing?
In the raw version of a dataset, the undefined UPR, the amount of reference product is not always 1. For example, the dataset “cotton production, CN” has a reference flow of 1000kg of cotton fibre. Additionally, an allocateable by-product, cotton seed, results from this activity.

Whenever the amount of the reference product is not 1 in the undefined UPR, it is scaled to 1 when a system models is applied. With that, also the amounts of all exchanges are scaled accordingly. However, it must be noted that the amounts of the other exchanges are not necessarily divided by 1000 as well. It can be seen from the table, that the production of 1000kg of cotton fibre result in carbon dioxide emissions of 335kg, while in the cut-off system model 1 kg of fluting medium is responsible for only 0.269 kg carbon dioxide. The reason is that this dataset has also produces a by-product. Hence, when applying a system model the exchanges are being allocated between the different reference/by-products according to the methodology of the respective system model.
What does the version number of the database mean?
What is an activity in ecoinvent version 3?
What are global background activities and where do they come from?
What is a market and how is it created?
In which situations are direct activity links used?
Why is the reference product of the treatment activities negative?
What is linking and what happens during the linking process? Attributional System Model
What is linking and what happens during the linking process? Consequential System Model
What is allocation at the point of substitution (APOS)?
What do the shortcuts, such as CH, RER, RoW and GLO mean?
The ecoinvent database in Environmental Product Declarations (EPDs)
What does it mean, when the production volume of an activity is zero?
Why is the “Allocation, default” system model not available in the ecoquery anymore?
How do I calculate the amount of transport in the market?
What is the Rest-of-the-World (RoW) and how is it calculated?
Why is the LCIA score of a certain product negative?
What are the UUID numbers and how do they work?
How to interpret the uncertainty fields in ecoinvent?
What are the LCIA methods ecoinvent is publishing the impact assessment results for?
APOS: why do I have carrots on my recycled aluminium?