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The Joy of Slack

Posted by Robert L Wears on Thursday January 30th, 2014

The Joy of Slack

Robert L Wears, MD, MS, PhD

“Slack.  The term reeks of inefficiency.”1  It suggests a sloppiness, a looseness of coordination, a falling behind the tempo of operations.  “Slackers” are generally not among those whose performance we praise or wish to emulate.

Over 20 years ago, Paul Schulman argued for the counterintuitive virtues of slack1.  Slack can take different forms.  Resource slack is a surplus of equipment, supplies, or personnel relative to current demands.  It can be viewed conventionally as non-productive waste, or alternatively as a hedge against unexpected demands, a buffer against external or internal shocks.  Temporal slack is a bit of extra time.  A nice example of temporal slack is the “scheduled hold” in NASA’s countdown procedures; NASA’s engineers recognized that although they could not predict precisely what problems they would encounter during a countdown, they could be reasonably sure they would encounter some; so they provided additional time in which to address them rather than have an unexpected “glitch” cause them to miss a launch window.  Temporal slack can be viewed either as unnecessary waiting, or as an opportunity to consolidate resources or address disturbances.  Procedural or control slack involves the under-specification of either processes or authority.  It can be viewed as ambiguity and lack of control, or as potentially useful flexibility and protection against the dysfunctional potential of centralized authority2.  Finally, conceptual slack is a heterogeneity of perspectives on a system’s state, functions, and environment.  It can be viewed as confusion and conflict in shared understanding, or as maintaining a “requisite variety” of viewpoints, a protection against hubristic “groupthink”3-5.  Sadly, Schulman’s insights have been all but forgotten in the Cartesian-Newtonian vision of a progressively more perfectable world6.

Slack in its many varieties serves to loosen coupling and so enhance safety7.  It would seem a necessary but not sufficient resource supporting resilient performance.  Unfortunately, slack is under tremendous pressure, especially in healthcare as these systems are doubly beset by economic pressures and by the rationalising impulse to drive out waste and to “engineer” everything – “to establish once and for all consistent, unambiguous guidelines and to tolerate no competing organizational perspectives.”1  Resource and temporal slack are threatened by the drive for greater economic efficiency, while control and conceptual slack are threatened by the hegemonic agenda of technical rationality8.  The voices crying out for a variety of “improvement” efforts – the measure and manage orthodoxy of Lean, Six Sigma, TQI, etc. – are popular, loud, and increasingly bristling with external power, leaving advocates for slack as lonely voices crying in the wilderness. 

But the erosion of slack is a grave threat.  Slack is loosely analogous to cash reserves in finance, or carrying capacity in ecosystems; one can temporarily improve performance by borrowing from these reserves, but depleting them too far not only drives the system to the point of collapse, but also impoverishes its ability to continue and recover after collapse9

To have safe and resilient systems of care, we will have to learn how to value slack, and in this valorization to take a take a “long view” – because in the long run, things that never happened before happen all the time10.  Aaron Wildavsky uses the example of Mario Puzo’s Godfather, whoworked very hard at doing favours for people, even though he expected no immediate return or even any return at all.  He notes the Godfather wished “to have others beholden to him in diverse and unspecified ways, precisely because he knows that he won’t know in advance who he will need or when or for what purpose”11.  By accumulating nonspecific resources – building slack -- he increases the odds he can meet unexpected challenges.

Unfortunately, when confronted with internal problems or external threats, many managers respond with “threat rigidity” – actions that restrict resources and tighten control, ironically reducing slack at just those times when it is most needed.  When greater performance (faster, better, cheaper) is needed but when achieving it imposes demands on limited slack, it would be better to find ways of increasing slack before pushing for higher performance.  The inevitability of tradeoffs among competing dimensions of performance12 underscores the need to identify and preserve slack. 

What we need now are a few good “partisans of the neglected perspective” who can “know that they won’t know” and so act to accumulate and preserve slack.  To follow the cheers and high hopes that dominate conference proceedings, consultants’ pronouncements, and large parts of the ‘improvement’ literature is to engage in self-delusion and to risk catastrophe, because ultimately, reality inevitably trumps utopian scientism, and “nature cannot be fooled”13.

 

References and further readings

  1. Administration and Society 1993;25(3):353 - 372.
  2. New Technology and Human Error. Chichester, UK: John Wiley & Sons; 1987: pp 111 - 120.
  3. Organization Science 1991;2(1):1 - 13.
  4. Qual Saf Health Care 2003;12(6):465-471.
  5. Cybernetica 1958;1:83 - 99.
  6. Drift into Failure:  From Hunting Broken Components to Understanding Complex Systems. Farnham, UK: Ashgate; 2011, 220 pages.
  7. Normal Accidents:  Living With High-Risk Technologies. New York, NY: Basic Books; 1984: pp 62-100.
  8. The Reflective Practitioner:  How Professionals Think in Action. New York, NY: Basic Books; 1982: pp 21 - 69.
  9. http://www.systemdynamics.org/DL-IntroSysDyn/sshp.htm, accessed 25 January 2014.
  10. The Limits of Safety:  Organizations, Accidents, and Nuclear Weapons. Princeton, NJ: Princeton University Press; 1993, 286 pages.
  11. Searching for Safety. New Brunswick, NJ: Transaction Books; 1991, 254 pages.
  12. Intelligent Systems, IEEE 2011;26(6):67-71.
  13. Report of the Presidential Commission on the Space Shuttle Challenger Accident:  Appendix F - Personal Observations on Reliability of Shutte. Washington, DC: US Government Printing Office; 1986, http://history.nasa.gov/rogersrep/v2appf.htm, accessed 22 October 2013.

Add your comment

February 16th, 2014 by Robert L Wears
Gary notes that healthcare improvement efforts such as Lean tend to use the factory as a model – more specifically, the assembly line. This is an example of the impoverishment of thinking in this area. In business, there are many different models of production besides the assembly line, and some argument that the characteristics of the product (along a continuum from single bits of custom work, as in a job shop, to innumerable bits of identical ‘thingies’, as in electric power production) should match model of production (job shop to batch process to assembly line to continuous production), and failure to match appropriately leads either to inefficiency or ineffectiveness. There is a nice paper on the “product – process matrix” in Harvard Business Review1,2. There may be some parts of healthcare that fit an assembly line model, but my feeling is most do not, so the lack of requisite understanding in trying to force all care processes into this model is likely to create problems.
His aside on schools as factories is also interesting. James Scott has noted the same similarity, and pointed out that the modern school developed about the same time as the textile factory, and has many similarities: captive subjects, division of labour, regimentation by time, etc. Both are part of the high modernist, utopian scientism that ignores externalities and practical knowledge-in-action.
Wrae gives a great example of the short-sided focus on efficiency, not paying for 15 minutes of overlap – in an era in which nurses routinely stay late on over 80% of their shifts, take only half their scheduled breaks, and average 55 minutes longer than scheduled overall3. And our worsening shortage of nurses is a mystery?
References and further readings
1. Hayes RH, Wheelwright SC. Link manufacturing process and product life cycle. Harvard Business Review 1979;57(January-February):133 - 140.
2. Hayes RH, Wheelwright SC. The dynamics of process-product lifecycles. Harvard Business Review 1979;57(March-April):127 - 136.
3. Rogers AE, Hwang W, Scott LD, et al. The Working Hours Of Hospital Staff Nurses And Patient Safety. Health Aff 2004;23(4):202-212.

February 5th, 2014 by Gary Wong
Hi, Bob. You are bang on. Great piece on why slack is an imperative. You've covered most of the bases. I'd like to add a few more we've learned from the military, aviation, energy & utilities, transportation et al industries.
1. Enough has been said that the Healthcare industry in a complex adaptive system (CAS). It also means we must go beyond traditional reductionist "the whole is equal to the sum of its parts" thinking. This is the problem I have with linear thinkers who analyze the parts (process, technology, people) separately and then put them back together expecting improvements. What they miss are the relationships and interactions that emerge and essentially define the CAS.
2. From a knowledge management perspective continuous improvement efforts focus on 'known knowns' and 'knowable unknowns'. They don't address 'unknowables' and 'unimaginables' simply because no one can by definition. But we are aware these events will arrive as negative Black Swans and positive serendipitous opportunities.
3. Strengthening CAS Robustness (able to take a hit) isn't enough. We must also build Resilience (able to early detect, perform fast recovery, and exploit emerging opportunities.)
4. To execute a resilience strategy, slack (standby equipment, looser-coupled processes, etc.) is necessary for fast recovery. Slack in the form of time to allow humans to interact is required, especially if chats focus on early detection as well as capturing an opportunity.
5. I haven't been directly involved with Lean in HC but I believe the dominant paradigm is the Hospital is a Factory. It would make sense since lean practices began in the manufacturing industry. Drive for efficiency to produce a faster, better, cheaper product. If true, now I understand why the HC industry is in so much trouble. Similar to Education which also follows the factory model:run classes like shift work, categorize children by age, grade them like products, send them through the K-12 production line.

What if the paradigm was changed so that a hospital was run like a Marriott hotel in the hospitality industry? Hmm, hospital... hospitality.... was there a connection some time ago that went astray??

Imagine if a hotel ran like a hospital. Guests would only be served meals at a certain starting at 5pm. Housemaids arrive at 8am and enter your room to begin their chores. No variation, no slack in the schedule but have a nice day.

Hotels run very efficiently but processes have built-in slack. If a guest arrives and a lineup builds, more service clerks appear. If you're not awake at 8am, the housemaid comes back later. Meals 24/7. And the #1 icon for slack is the concierge who's role is to wait around ready to serve you. Now that's a prime example of resilience: early detection of a guest in need of help.

Slack in the system enables Derek the hotel front desk-clerk to do what he did one snowy night in Atlanta. http://linkd.in/1eytjS4.

February 3rd, 2014 by Wrae Hill
Reliable processes with slack built in - Interactive Handover

Thanks Bob for the insights on slack in our systems and (dare I say) thinking. Your blog helped me think about simplifying my language so that it might be more accessible to those I work with.
“To have safe and resilient systems of care, we will have to learn how to value slack”

Interactive Handover
Clear communication is vital at all handovers and particularly when patients transfer out of Emergency (either home or admitted). We needed to find a way to better design our systems and roles to help clinicians with this process. Some key problems revealed by our data over the last year include;
1. All patient handovers are involve high potential for risk
2. Conflicting priorities between units/departments
3. Poor communication of the basics exposes patients to risk: Identity/ Diagnosis/ Recent changes
4. There are many opportunities to improve anticipatory planning; “what might happen next”
5. Limited available time for patient handover interaction (tools need to help simplify the message)

At Change of Shift the situation is worse, because a nursing handover is UNPAID time , (while tying your shoes) in my jurisdiction.
This is a recent problem. Over the last decade this paid “slack” has been repeatedly consumed (tightened) by well intentioned, yet constrained leaders seeking to find "inefficiencies" in systems.... why pay 2 nurses a 15 min overlap ? Unfortunately the evidence for paid handover was not solid. An underlying problem I see in the : "See one , do one , teach one" culture of healthcare is that fundamental communication rules and skills are not as highly valued as they are in military/ pre-hospital and aviation safety critical domains. There seems an underlying assumption that we all just pick up those skills on the job. (Not so much…)

The slack that has been lost is face: face interaction… crucial for effective handover. Further, Interaction (Interactive Handover) is not yet even a defined expectation (in our health system). The lack of systematic Nurse – Nurse Interaction manifests itself in:
a. Inability to connect nurse to nurse (by phone) to handover patients
b. Inability to receive report (by phone) from the primary ED RN for the patient
c. Inability to deliver report from to the primary receiving RN for the patient

So , lots of risks. We need reliable processes with slack built in.

We have been attempting to build more reliable processes with slack built in, Interactive Handover. Video : 4 min (ED to Med/Surg Handover) https://www.youtube.com/watch?v=bsltjAwzaZY

Thanks again Bob for the insights on slack in our systems

Wrae Hill - Manager of Human Factors and System Safety at Interior Health. Wrae.V.Hill@interiorhealth.ca

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Dr Wears is an emergency physician, Professor of Emergency Medicine at the University of Florida, and Visiting Professor in the Clinical Safety Research Unit at Imperial College London.  His further training includes a Master’s in computer science, a 1 year research sabbatical focused on psychology and human factors in safety Imperial, after and a PhD in resilience engineering from Mines ParisTech (Ecole Nationale Supérieure des Mines de Paris).  He serves on the board of directors of the Emergency Medicine Patient Safety Foundation, and multiple editorial boards, including Annals of Emergency Medicine, Human Factors and Ergonomics, the Journal of Patient Safety, and the International Journal of Risk and Safety in Medicine.  He has co-edited two books, Patient Safety in Emergency Medicine, and Resilient Health Care.  His research interests include technical work studies, resilience engineering, and patient safety as a social movement. 

 

Dr Wears is an emergency physician, Professor of Emergency Medicine at the University of Florida, and Visiting Professor in the Clinical Safety Research Unit at Imperial College London.  His further training includes a Master’s in computer science, a 1 year research sabbatical focused on psychology and human factors in safety Imperial, after and a PhD in resilience engineering from Mines ParisTech (Ecole Nationale Supérieure des Mines de Paris).  He serves on the board of directors of the Emergency Medicine Patient Safety Foundation, and multiple editorial boards, including Annals of Emergency Medicine, Human Factors and Ergonomics, the Journal of Patient Safety, and the International Journal of Risk and Safety in Medicine.  He has co-edited two books, Patient Safety in Emergency Medicine, and Resilient Health Care.  His research interests include technical work studies, resilience engineering, and patient safety as a social movement. 

 

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