Table A87.

Result report on EKE question 3

Overview of the results of the Expert Knowledge Elicitation Question 3
Parameter	Proportion of organic waste going to private composting
Stratification	Countries in the climatically suitable area/only one average of the climatically suitable area
Question	Compared to the waste counted in the statistics of Eurostat, what additional proportion of organic waste is going to private composting?
Unit	[%], theoretical restriction: 0–100%
Results	P1%	P2.5%	P5%	P10%	P16.7%	P25%	P33.3%	P50%	P66.7%	P75%	P83.3%	P90%	P95%	P97.5%	P99%
Elicited values	2%					8%		13%		25%					40%
EKE results	2.0%	2.2%	2.6%	3.6%	5.1%	7.1%	9.4%	14%	21%	24%	28%	32%	36%	38%	40%
Fitted distribution	BetaGeneral (0.85283, 1.555, 0.0188, 0.425)
Figure (a): Comparison of elicited and fitted values/density function to describe the remaining uncertainties of the parameter							Figure (b): Cumulative distribution function (CDF) of the likelihood of the parameter

Summary of the evidence used for the evaluation
Literature on home composting (e.g. see: Colón et al., 2010; Tatàno et al., 2015; Stenmarck et al., 2016; Žitnik and Vidic, 2016; ISPRA, 2021; Sulewski et al., 2021)
Main uncertainties
Lack of data on volumes of organic waste treated as home composting and on conditions of home composting
Reasoning for a scenario which would lead to a reasonable high proportion	The judgement on the upper limit considers that Level of population living in houses (50%)/High rate of private compost in a survey/Complete organic part going to private compost Slovenia is an example for a high rate 48% of private compost, but high proportion of living in houses
Reasoning for a scenario which would lead to a reasonable low proportion	The judgement on the lower limit considers that It is above 0%, because it includes all kind of disposal of organic waste (dumping, feeding, etc.), not only composted waste 24% of population is living in rural areas
Fair estimate as judgement on the weighted evidence	The judgement on the median considers that Statistics from 5 countries mainly Northern/Western EU shows about 8%, for the countries of the climatically suitable area the home composting will be higher High part of the population living in rural areas It includes all kind of disposal of organic waste (dumping, feeding, etc.), not only composted waste
Precision of the judgement as description of remaining uncertainties	The judgement on the interquartile range considers that High uncertain on both sides of the median value
Experts	Antoon LOOMANS, Panos MILONAS, Klara NICOVA, Giuseppe STANCANELLI, Hans‐Hermann THULKE
Facilitator/Reporter	Olaf MOSBACH‐SCHULZ (facilitator)
Observers	na
Date and place of the EKE	Virtual meeting on 9 January 2023