QuEST Mental Health Data for Improvement Network

SPC ChartsAlison RedpathSenior Information Analyst

Statistical Process Control (SPC)

Run Chart vs SPC

Run Chart SPC

Displays data as a picture that shows variation over time

Simple rules make it easy to spot and interpret patterns (and not over interpret)

Shows signals of change Is more sensitive and shows special causes of variation

Enables you to see the individual data points and the average at the same time

Shows the natural range, useful in planning

Needs small amount of data Need 20-30 data points as a minimum

One way to create Many different types exist

Which chart?

What typeof data?

Can both occurrences and non-occurrences

be counted?

How manyobservations

per sub-group?

Continuous Discrete

Are the sub-groups equal

size?

Are there equal areas of opportunity?

XbarR chart

XbarS chart

XmR chart

u-chartc-chart p-chart np-chart

12-10

>10 Yes NoYesNo

Yes

No

Which chart?

What typeof data?

Do we have both pass/fail, yes/no?

How many are represented by

one data point?

Measure Count

Do all data points

represent the same number?

Is the chance the same for each point?

XbarR chartXbarS chart

XmR chart

u-chartc-chart p-chart np-chart

12-10

>10 Yes NoYesNo

Yes

No

Mental Health likely charts

• Waiting times breachers per month % p-chart• DNA % - p-chart• New:follow-up ratio per month p-chart• Number of referrals per month c-chart• Number of patients on the caseload per month c-chart• Total waiting list size c-chart• Average waiting time per month XbarR chart• Average waiting time per day XbarS chart• Waiting time per patient XmR chart

Method

SPC tool

Equations

https://www.moresteam.com/toolbox/statistical-process-control-spc.cfm

Theory

Rules for interpretation

• Any point outside the control limits• 2/3 points in the outer third• 15 consecutive points in the inner third• 8 or more above or below the average• 6 or more in a trend

Example

• Number of Adult Psychiatry Appointments DNA'd in NHS Somewhere between January 2011 and January 2013

Example

Further information

• http://en.wikipedia.org/wiki/Control_chart has a list of different control chart types, with links to how to construct each of them

• Register with IHI.org and then find the webex On Demand: Using Run and Control Charts to Understand Variation

Further support

Alison RedpathSenior Information Analyst

QuEST Mental Health01312443284

alison.pickering@scotland.gsi.gov.uk