PICSO: Population, Intervention, Control, Setting, Outcome

Things like this NICE manual talk about setting, when formulating a search question, and there is the SPICE scheme, where S is the setting.    But I am not sure I have seen a version of the PICO grid which includes setting.

If there is one, it would be good to know about it and you can tell me in the comments.&nbsp But if not, I may have just invented it.   But I can't claim the credit.   My eye was caught by a Guardian article today about whether face masks work to prevent the spread of COVID-19, and my eye was particularly caught because the author is Professor Trisha Greenhalgh of Oxford University, author of How to read a paper,  a staple of any reading list about critical appraisal.

Greenhalgh discusses how you would design a randomised trial to examine whether wearing a face mask prevents COVID-19 infection in others.   Read the article, it is very well worth reading, an exploration of trial design, philosophy of science, and what evidence is possible.

Greenhalgh writes:

"Let's therefore test, in all members of the general public (population), the impact of cloth face coverings (intervention) compared to no coverings (control) in public places (setting) for preventing infection in other members of the public (outcome)."

So I had the thought  - that is a scheme to use to plan a literature search, and to formulate an answerable question:

Population
Intervention
Control
Setting
Outcome

= PICSO

I then had the thought - isn't this PICOS?   But in PICOS, the S is Study design. 

So, PICSO is not the same as PICOS.    A PubMed search for PICSO finds a few things about "pressure-controlled intermittent coronary sinus occlusion", and one possibly two about "physiological contributions in spontaneous oscillations", and one where it might actually be PIC50, but nothing about literature searching or evidence based practice.  Indeed, PubMed asks "Did you mean picos?".   There are far more about picos, using PICOS with S as Study Design (and some about the Picos de Europa in Northern Spain).

C could be "comparison".

I've used this search example (admittedly not a very answerable question) with nursing and midwifery students:

Compression stockings to prevent deep vein thrombosis in middle aged hospital inpatients>

In the session, P = middle aged hospital inpatients, I = compression stockings, C = implicitly, no stockings; O = DVT

With PICSO:

P - middle aged people
I - compression stockings
C - no stockings
S - hospital
O - DVT

I think there is scope for PICSO as a search planning tool and as an alternative to PICO as a tool to help devise answerable questions.