Sortition is jargon for selection by lots, think of jury service, I discuss this further in Part 2 - Assess - Vision - Fleshing it out.
When people talk about Participative Democracy they are referring to the use of randomly selected citizens assemblies to assess and make recommendations on difficult topics, see Sortition Foundation . This is building up the case empirically by showing that citizens can get to grips with difficult problems. In a holistic political economy all those parts of the state that are putting policy into action and running things (on behalf of citizens) should have randomly selected citizens as part of their management - this is a more radical position based on the adage 'anything for me, without me, is against me' and it is needed because these agencies, ALMOS etc. are patronage systems and often behave high handily (as we have seen). Ministries can be so large that ministerial oversight is practically none existent; the Information on Public Bodies cited earlier shows ministrial reviews may be bi-annual.
See also Reybrook: Against Elections, The Case for Democracy - Bibliography
Part 2 - Assess - Timeline - Present - Poor Governance - Summing up - political implications