The truth behind takt time

A few months ago my wife ordered a hole punch from Amazon one evening. It cost £5.49. The following morning at 8.00 there was a knock at the door. The hole punch was delivered.

That really is as much as I know for a fact about Amazon’s business processes. I was, therefore, shaken by an item on BBC News alleging Amazon workers face ‘increased risk of mental illness’. I don’t think the quotes make that anything other than an alarming headline. The item trailed a BBC documentary The Truth Behind The Click. UK readers can see the documentary here on BBC iPlayer. I thought that I would wait until I watched the documentary before I commented.

Having now watched it, I think it is difficult to draw any conclusions from the programme. Its tone was so plainly tendentious. The BBC had sent a covert reporter with a video camera into an Amazon warehouse, he having misrepresented himself as a job seeker. Some of the video, taken from the perspective of an Amazon employee picking in a warehouse, looked to me as though it was shown speeded up.

Professor Sir Michael Marmot, an expert in public health, was shown the video, I presume the same limited and selective one shown on the BBC. He observed that:

The characteristics of this type of job, the evidence shows, increase the risk of mental illness and physical illness.

Sadly there is no analysis. We were not told what characteristics, what the supposed levels of safety or what the supporting evidence. There was no quantitative data drawn from more than one individual.

Part of the problem with the programme was, I think, that three principle issues have been conflated here.

  • The general nature of repetitive manual work.
  • The psychological impact of working to an externally set “drum beat”.
  • The physical and cognitive effects of working at a particular rate.

Repetitive work

Repetitive work has always been with us. Some people find in it dignity and liberation. The Buddhist practice of samu, repetitive physical work performed with mindfulness, is part of Zen spiritual dicipline and the quest for enlightenment. Conversely, socialist pioneer William Morris believed that we should all be composing epic poems in our heads while sat weaving at the loom.

That being said, such work is not for everybody. I got the impression that Amazon were fairly clear to new employees as to what was involved. This is where recruitment is a key business process, identifying people who will fit with this type of role and stick with it.

However, I see nothing in general sinister about such work.

Drum beat

What delivered that hole punch so quickly was the “drum beat” that regulates work along the supply chain. This is a fundamental part of the Toyota Production System and lean operations generally.

The takt time specifies the rate at which products are being despatched to customers. That sets the rate at which pickers need to work. If the pickers work too quickly then packages build up in front of the despatch area. If too slowly, the despatch area stands idle. Both entail cost or delay that has to be passed on to the customer. The customer suffers.

The programme interviewed workers who felt the “drum beat”, announced through the bleep on a hand held electronic scanner, dehumanising. The BBC journalist clearly shared their view. The workers felt this deprived them of autonomy. They felt that they were not encouraged to think of [them]selves as human beings.

We do not show enough respect for boring work. We tend to sentimentalise and even glamorise the sort of active participation in work that too often results from having to resolve a non-conformance, a defect, a delay or an emergency. That is not useful work, no matter how much satisfaction it offers the employee.

I sometime sense a bien pensant nostalgia for the days when millions were employed in repetitive tasks on piece work. I think the BBC especially self indulgent on this matter. Piece work of course incentivises a worker to produce as much as they can even if that increases costs to the company in storing it until it can be used, if it ever is. The benefit of the drum is that the worker is required to produce no more or less than society needs. The laudable aim of lean operations is to reduce waste, Toyota use the Japanese term muda.

What I think was missing at Amazon was engagement of all employees in improvement. The usual quid pro quo for diligently following the drum is that part of the day is spent off-line in improvement work where an employee can, if so inclined, exercise their ingenuity. However, I am aware that the BBC reporter was recruited for the Christmas rush. That is not a period that anybody devotes to improvement work. Production is king. Improvement should have been prioritised earlier in the year when volumes were slow.

I think though that there is still an opportunity for a periodic review of the voice of the customer with all staff. It is focus on the customer that ultimately legitimises and justifies the discipline. I think Amazon staff would appreciate being reminded of just how quickly their orders are getting to customers, the variety of desires satisfied so promptly and the volume of transactions despatched, all through their discipline and focus on the drum.

Perhaps Amazon do this but the reporter didn’t stick around long enough to hear.

Work rate

This is the toughest part of the allegations to analyse. Was the takt time just set too quick for human capability? There is probably some flexibility in setting the rate for any individual as capacity can be increased by employing more pickers. There must be some limit on the number of pickers as the warehouse aisles will only accommodate so many on the move. However, as I said above, I found the overall tone of the programme so tendentious that I cannot take its criticisms at face value. No analysis by Professor Marmot was presented. Amazon have serious legal obligations to provide their workers with a safe system of work and to carry out health surveillance. Amazon have to cope with the real costs of absenteeism, staff turnover and litigation. I would be surprised if they had not analysed work demands thoroughly and diligently.

I do confess to feeling uncomfortable at the practice of terminating employment on the third consecutive day’s sick leave but, ultimately, it is a matter for Amazon.

I think that my conclusion from watching the programme is that it is critical to maintain all employees’ extrinsic motivation by the voice of the customer through constant review and emphasis of how an individual’s discipline contributes to the overall market impact. Goal deployment helps. Beyond that, I’m not persuaded by the BBC’s criticism.

Suicide statistics for British railways

I chose a prosaic title because it’s not a subject about which levity is appropriate. I remain haunted by this cyclist on the level crossing. As a result I thought I would delve a little into railway accident statistics. The data is here. Unfortunately, the data only goes back to 2001/2002. This is a common feature of government data. There is no long term continuity in measurement to allow proper understanding of variation, trends and changes. All this encourages the “executive time series” that are familiar in press releases. I think that I shall call this political amnesia. When I have more time I shall look for a longer time series. The relevant department is usually helpful if contacted directly.

However, while I was searching I found this recent report on Railway Suicides in the UK: risk factors and prevention strategies. The report is by Kamaldeep Bhui and Jason Chalangary of the Wolfson Institute of Preventive Medicine, and Edgar Jones of the Institute of Psychiatry, King’s College, London. Originally, I didn’t intend to narrow my investigation to suicides but there were some things in the paper that bothered me and I felt were worth blogging about.

Obviously this is really important work. No civilised society is indifferent to tragedies such as suicide whose consequences are absorbed deeply into the community. The report analyses a wide base of theories and interventions concerning railway suicide risk. There is a lot of information and the authors have done an important job in bringing together and seeking conclusions. However, I was bothered by this passage (at p5).

The Rail Safety and Standards Board (RSSB) reported a progressive rise in suicides and suspected suicides from 192 in 2001-02 to a peak 233 in 2009-10, the total falling to 208 in 2010-11.

Oh dear! An “executive time series”. Let’s look at the data on a process behaviour chart.


There is no signal, even ignoring the last observation in 2011/2012 which the authors had not had to hand. There has been no increasing propensity for suicide since 2001. The writers have been, as Nassim Taleb would put it, “fooled by randomness”. In the words of Nate Silver, they have confused signal and noise. The common cause variation in the data has been over interpreted by zealous and well meaning policy makers as an upward trend. However, all diligent risk managers know that interpretation of a chart is forbidden if there is no signal. Over interpretation will lead to (well meaning) over adjustment and admixture of even more variation into a stable system of trouble.

Looking at the development of the data over time I can understand that there will have been a temptation to perform a regression analysis and calculate a p-value for the perceived slope. This is an approach to avoid in general. It is beset with the dangers of testing effects suggested by the data and the general criticisms of p-values made by McCloskey and Ziliak. It is not a method that will be a reliable guide to future action. For what it’s worth I got a p-value of 0.015 for the slope but I am not impressed. I looked to see if I could find a pattern in the data then tested for the pattern my mind had created. It is unsurprising that it was “significant”.

The authors of the report go on to interpret the two figures for 2009/2010 (233 suicides) and 2010/2011 (208 suicides) as a “fall in suicides”. It is clear from the process behaviour chart that this is not a signal of a fall in suicides. It is simply noise, common cause variation from year to year.

Having misidentified this as a signal they go on to seek a cause. Of course they “find” a potential cause. A partnership between Network Rail and the Samaritans, Men on the Ropes, had started in January 2010. The programme’s aim was to reduce suicides by 20% over five years. I genuinely hope that the programme shows success. However, the programme will not be assisted by thinking that it has yet shown signs of improvement.

With the current mean annual total at 211, a 20% reduction entails a new mean of 169 annual suicides.That is an ambitious target I think, and I want to emphasise that the programme is entirely laudable and plausible. However, whether it succeeds is to be judged by the figures on the process behaviour chart, not by any post hoc rationalisation. This is the tough discipline of the charts. It is no longer possible to claim an improvement where that is not supported by the data.

I will come back to this data next year and look to see if there are any signs of encouragement.

Trust in data – IV – trusting the team

Today (20 November 2013) I was reading an item in The Times (London) with the headline “We fiddle our crime numbers, admit police”. This is a fairly unedifying business.

The blame is once again laid at the door of government targets and performance related pay. I fear that this is akin to blaming police corruption on the largesse of criminals. If only organised crime would stop offering bribes, the police would not succumb to taking them in consideration of repudiating their office as constable, so the argument might run (pace Brian Joiner). Of course, the argument is nonsense. What we expect of police constables is honesty even, perhaps especially, when temptation presents itself. We expect the police to give truthful evidence in court, to deal with the public fairly and to conduct their investigations diligently and rationally. The public expects the police to behave in this way even in the face of manifest temptation to do otherwise. The public expects the same honest approach to reporting their performance. I think Robert Frank put it well in Passions within Reason.

The honest individual … is someone who values trustworthiness for its own sake. That he might receive a material payoff for such behaviour is beyond his concern. And it is precisely because he has this attitude that he can be trusted in situations where his behaviour cannot be monitored. Trustworthiness, provided it is recognizable, creates valuable opportunities that would not otherwise be available.

Matt Ridley put it starkly in his overview of evolutionary psychology, The Origins of Virtue. He wasn’t speaking of policing in particular.

The virtuous are virtuous for no other reason that it enables them to join forces with others who are virtuous, for mutual benefit.

What worried me most about the article was a remark from Peter Barron, a former detective chief superintendent in the Metropolitan Police. Should any individual challenge the distortion of data:

You are judged to be not a team player.

“Teamwork” can be a smokescreen for the most appalling bullying. In our current corporate cultures, to be branded as “not a team player” can be the most horrible slur, smearing the individual’s contribution to the overall mission. One can see how such an environment can allow a team’s behaviours and objectives to become misaligned from those of the parent organisation. That is a problem that can often be addressed by management with a proper system of goal deployment.

However, the problem is more severe when the team is in fact well aligned to what are distorted organisational goals. The remedies for this lie in the twin processes of governance and whistleblowing. Neither seem to be working very well in UK policing at the moment but that simply leaves an opportunity for process improvement. Work is underway. The English law of whistleblowing has been amended this year. If you aren’t familiar with it you can find it here.

Governance has to take scrutiny of data seriously. Reported performance needs to be compared with other sources of data. Reporting and recording processes need themselves to be assessed. Where there is no coherent picture questions need to be asked.

Trust in data – II

I just picked up on this, now not so recent, news item about the prosecution of Steven Eaton. Eaton was gaoled for falsifying data in clinical trials. His prosecution was pursuant to the Good Laboratory Practice Regulations 1999. The Regulations apply to chemical safety assessments and come to us, in the UK, from that supra-national body the OECD. Sadly I have managed to find few details other than the press reports. I have had a look at the website of the prosecuting Medicines and Healthcare Products Regulatory Agency but found nothing beyond the press release. I thought about a request under the Freedom of Information Act 2000 but wonder whether an exemption is being claimed pursuant to section 31.

It’s a shame because it would have been an opportunity to compare and contrast with another notable recent case of industrial data fabrication, that concerning BNFL and the Kansai Electric contract. Fortunately, in that case, the HSE made public a detailed report.

In the BNFL case, technicians had fabricated measurements of the diameters of fuel pellets in nuclear fuel rods, it appears principally out of boredom at doing the actual job. The customer spotted it, BNFL didn’t. The matter caused huge reputational damage to BNFL and resulted in the shipment of nuclear fuel rods, necessarily under armed escort, being turned around mid-ocean and returned to the supplier.

For me, the important lesson of the BNFL affair is that businesses must avoid a culture where employees decide what parts of the job are important and interesting to them, what is called intrinsic motivation. Intrinsic motivation is related to a sense of cognitive ease. That sense rests, as Daniel Kahneman has pointed out, on an ecology of unknown and unknowable beliefs and prejudices. No doubt the technicians had encountered nothing but boringly uniform products. They took that as a signal, and felt a sense of cognitive ease in doing so, to stop measuring and conceal the fact that they had stopped.

However, nobody in the supply chain is entitled to ignore the customer’s wishes. Businesses need to foster the extrinsic motivation of the voice of the customer. That is what defines a job well done. Sometimes it will be irksome and involve a lot of measuring pellets whose dimensions look just the same as the last batch. We simply have to get over it!

The customer wanted the data collected, not simply as a sterile exercise in box-ticking, but as a basis for diligent surveillance of the manufacturing process and as a critical component of managing the risks attendant in real world nuclear industry operations. The customer showed that a proper scrutiny of the data, exactly what they had thought that BNFL would perform as part of the contract, would have exposed its inauthenticity. BNFL were embarrassed, not only by their lack of management control of their own technicians, but by the exposure of their own incapacity to scrutinise data and act on its signal message. Even if all the pellets were of perfect dimension, the customer would be legitimately appalled that so little critical attention was being paid to keeping them so.

Data that is properly scrutinised, as part of a system of objective process management and with the correct statistical tools, will readily be exposed if it is fabricated. That is part of incentivising technicians to do the job diligently. Dishonesty must not be tolerated. However, it is essential that everybody in an organisation understands the voice of the customer and understands the particular way in which they themselves add value. A scheme of goal deployment weaves the threads of the voice of the customer together with those of individual process management tactics. That is what provides an individual’s insight into how their work adds value for the customer. That is what provides the “nudge” towards honesty.

Trust in data – I

I was listening to the BBC’s election coverage on 2 May (2013) when Nick Robinson announced that UKIP supporters were five times more likely than other voters to believe that the MMR vaccine was dangerous.

I had a search on the web. The following graphic had appeared on Mike Smithson’s PoliticalBetting blog on 21 April 2013.

MMR plot

It’s not an attractive bar chart. The bars are different colours. There is a “mean” bar that tends to make the variation look less than it is and makes the UKIP bar (next to it) look more extreme. I was, however, intrigued so I had a look for the original data which had come from a YouGov survey of 1765 respondents. You can find the data here.

Here is a summary of the salient points of the data from the YouGov website in a table which I think is less distracting than the graphic.

Voting   intention Con. Lab. Lib. Dem. UKIP
No. Of   respondents 417 518 142 212
% % % %
MMR safe 99 85 84 72
MMR unsafe 1 3 12 28
Don’t know 0 12 3 0

My first question was: Where had Nick Robinson and Mike Smithson got their numbers from? It is possible that there was another survey I have not found. It is also possible that I am being thick. In any event, the YouGov data raises some interesting questions. This is an exploratory date analysis exercise. We are looking for interesting theories. I don’t think there is any doubt that there is a signal in this data. How do we interpret it? There does look to be some relationship between voting intention and attitude to public safety data.

Should anyone be tempted to sneer at people with political views other than their own, it is worth remembering that it is unlikely that anyone surveyed had scrutinised any of the published scientific research on the topic. All will have digested it, most probably at third hand, through the press, internet, or cooler moment. They may not have any clear idea of the provenance of the assurances as to the vaccination’s safety. They may not have clearly identified issues as to whether what they had absorbed was a purportedly independent scientific study or a governmental policy statement that sought to rely on the science. I suspect that most of my readers have given it no more thought.

The mental process behind the answers probably wouldn’t withstand much analysis. This would be part of Kahneman’s System 1 thinking. However, the question of how such heuristics become established is an interesting one. I suspect there is a factor here that can be labelled “trust in data”.

Trust in data is an issue we all encounter, in business and in life. How do we know when we can trust data?

A starting point for many in this debate is the often cited observation of Brian Joiner that, when presented with a numerical target, a manager has three options: Manage the system so as to achieve the target, distort the system so the target is achieved but at the cost of performance elsewhere (possibly not on the dashboard), or simply distort the data. This, no doubt true, observation is then cited in support of the general proposition that management by numerical target is at best ineffective and at worst counter productive. John Seddon is a particular advocate of the view that, whatever benefits may flow from management by target (and they are seldom championed with any great energy), they are outweighed by the inevitable corruption of the organisation’s data generation and reporting.

It is an unhappy view. One immediate objection is that the broader system cannot operate without targets. Unless the machine part’s diameter is between 49.99 and 50.01 mm it will not fit. Unless chlorine concentrations are below the safe limit, swimmers risk being poisoned. Unless demand for working capital is cut by 10% we will face the consequences of insolvency. Advocates of the target free world respond that those matters can be characterised as the legitimate voice of the customer/ business. It is only arbitrary targets that are corrosive.

I am not persuaded that the legitimate/ arbitrary distinction is a real one, nor how the distinction motivates two different kinds of behaviour. I will blog more about this later. Leadership’s urgent task is to ensure that all managers have the tools to measure present reality and work to improve it. Without knowing how much improvement is essential a manager cannot make rational decisions about the allocation of resources. In that context, when the correct management control is exercised, improving the system is easier than cheating. I shall blog about goal deployment and Hoshin Kanri on another occasion.

Trust in data is just a factor of trust in general. In his popular book on evolutionary psychology and economics, The Origins of Virtue, Matt Ridley observes the following.

Trust is as vital a form of social capital as money is a form of actual capital. … Trust, like money, can be lent (‘I trust you because I trust the person who told me he trusts you’), and can be risked, hoarded or squandered. It pays dividends in the currency of more trust.

Within an organisation, trust in data is something for everybody to work on building collaboratively under diligent leadership. As to the public sphere, trust in data is related to trust in politicians and that may be a bigger problem to solve. It is also a salutary warning as to what happens when there is a failure of trust in leadership.