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# The role of Lean Management practices in the valorisation of neurodiverse people in production

Matteo Zanchi¹[0000-0002-9834-0489], Paolo Gaiardelli¹[0000-0002-2207-3628] and Giuditta Pezzotta¹[0000-0001-7983-8356]

¹ Department of Management, Information and Production Engineering, University of Bergamo, Viale Marconi 5, Dalmine (BG), Italy
matteo.zanchi@unibg.it, paolo.gaiardelli@unibg.it, giuditta.pezzotta@unibg.it

**Abstract.** Increasing awareness on the widespread presence of people with neurodiverse traits among manufacturing companies has been orienting Lean managers to understand how to ease the inclusion of such individuals to working environments. Neurodiversity, intended as atypical neurological developments due to natural variations of the human brain, is not a marker of neurological diseases, but rather of a different way the brain works. As such, people with neurodiverse traits possess a set of strengths and weaknesses that are not common among other workers, thus resulting in significant advantages for production effectiveness. This paper aims to understand how Lean Management techniques may unleash the full potential of neurodiverse people, enhancing their key assets and limiting their weak points, by putting into relation, from a human factor perspective, each tool with the neurodiversity they deal with, in a dedicated framework.

**Keywords:** Lean Management, Neurodiversity, Human Factors.

## 1 Introduction

The growing awareness regarding the wider presence of neurodiverse conditions among the population such as Attention Deficit and Hyperactivity Disorder (ADHD), autism and dyslexia, which have an overall prevalence oscillating between 16% and 16.6% worldwide [1], has led to the question in recent times as to whether the current working environments are inclusive in respect of the people affected by such conditions.

A more accommodating workplace may in fact support neurodiverse people in the execution of different activities with a lower degree of stress and anxiety, often generated by specific tasks that may put these people in discomfort. However, working environments are not usually designed for the needs of neurodiverse people who, consequently, are substantially excluded from the labour market. For example, it is only in the US, that the percentage of working age people affected by neurodiverse condition amounts to 37%, as compared to 79% of neurotypical individuals [2].

Whenever an attempt is made to render the working place more inclusive, Lean methodology can be considered as a possible way to pursue this mission [3]. Derived from the Japanese tradition, Lean Management methodology puts the human factor in the
spotlight, as underlined by the Hitozukuri (“the art of doing people well”) and provides
its effectiveness, by leveraging on people inclusion.

Given this premise, the inclusivity aspect typical of the Lean methodology has not yet
been proven for neurodiverse people, with particular reference to the capability of each
Lean practice to actually concur to the creation of a more supportive environment. The
aim of this paper is, therefore, to understand which benefits different Lean techniques
may bring to the working conditions of neurodiverse people, from a human factors per-
spective.

Following this brief introduction, the paper proceeds with the explanation of the meth-
odology used for the research (Section 2) and a summary description of the theoretical
background concerning human factors on the workplace, neurodiversity and Lean tech-
niques (Section 3). Following, three relationship maps linking neurodiversity and lean
methodologies are shown, within which each connection is contextualised in the light
of any specific human factor inferred from literature (Section 4). Last in this report,
Section 5 provides a final picture about the obtained results, in addition to clues and
hints for further research on the topic.

## 2 Methodology

From a methodological point of view, the research was led throughout two different
phases. The first of which consisted of a literature review regarding three main streams
of research, respectively: i) the expression of neurodiversity in the workplace, as it can
be useful to identify strengths and weaknesses of neurodiverse people in a typical man-
ufacturing environment [4]; ii) the redaction of a comprehensive set of Lean tools and
practices that may influence the work environment which in turn affects the perfor-
mances of neurodiverse people; and lastly iii) the provision of a complete set of human
factors related to the field of production, which may serve to properly frame the men-
tioned effects on the work sphere of the neurodiverse operator. Web of Science and
Google Scholar were the two main databases used to collect relevant papers on the
topics under exploration.

On the basis of the themes found in literature, three relationship maps (one for each
neurodiversity) were then drafted by three scholars participating in the research, to de-
pict whether the Lean practices could contribute to the creation of a more accommo-
dating working environment in respect of workers with neurodiverse traits. The impact
of such techniques was, in particular, placed in the context of those human factors that
mostly reflect the set of strengths and weaknesses characteristic of each specific neu-
rodiversity.

Then, the proposed maps were tested and validated by interviewing a Lean expert with
both theoretical and practical knowledge. Interviews were carried out through semi-
structured sessions to avoid excessive limitations to the discussion of such a vast and
multi-thematic subject.
# 3 Theoretical Background

## 3.1 Neurodiversity

The term 'neurodiversity', coined by Judy Singer in 1998 [5], generally refers to the varied spectrum of conditions underlying a different cognitive functioning of human beings. Although over the years the term neurodiversity has often been associated with a pathological condition, it actually implies an atypical neurological development, but merely as a natural variation of the human brain that is not characterised by an actual neurological deficit [1]. Whereas in a neurotypical subject cognitive scores, measured in relation to the dimensions of verbal skills, working memory, visual skills and processing speed, fall within a tolerance of one or two standard deviations from the average IQ (Intelligent Quotient) value, delineating a relatively flat cognitive profile; in neurodiverse individuals, scores vary significantly beyond this threshold, delineating peaks and troughs in correspondence of the respective strengths and weaknesses, thus forming a 'spiky' profile specific to each neurological condition.

The following analysis focuses on the three neurodiversity statistically most present in the population, each one characterised by a set of work-related difficulties and strengths [1]:

* **ADHD.** With a prevalence around 5% among the worldwide population, attention deficit hyperactivity disorder manifests itself, from early childhood onwards, with an evident difficulty in concentrating or working on the same task for a prolonged period of time, and a range of behaviours displaying hyperactivity and impulsivity. Despite these cognitive conditions, individuals affected by ADHD possess an elevated creative thinking [6] as well as a heightened visual-spatial reasoning [7];

* **Autism.** With a prevalence of 1.6% globally, autism is a neurodevelopmental condition characterised by difficulties in social and communicative interaction, sensory apathy, as well as the presence of narrow interests and an obsessive desire to maintain one's environment and living habits [8]. The strengths possessed by autistics include a strong memory ability [9], innovative thinking and detail observation [10];

* **Dyslexia.** With an incidence up to 10% of the global population, dyslexia is a specific reading disorder that manifests itself with a difficulty in decoding text. Nonetheless, people affected by dyslexia possess normal levels of intelligence [11] and also own a strong orientation towards entrepreneurialism [12], a strong sense of creativity and cognitive control [13], as well as visual reasoning skills [14].

## 3.2 Lean Tools

Existent literature distinguishes Lean Management (LM) practices as “hard” and “soft” [15], where the former includes a set of distinctive technical tools used to improve production processes, the latter more related to the managerial perspective [16]. In order to be fully effective, a Lean approach should be implemented considering both aspects, so that the effect of each one will be magnified by the other [17].
Table 1 reports the breakdown of the different identified LM categories into specific tools described in both from a theoretical and practical literature perspective.

<table><caption>**Table 1.** Breakdown of Bortolotti [16] LM practices in single LM tools</caption><thead><tr><th>Type of Practice</th><th>LM Practice</th><th>LM Tools</th></tr></thead><tbody><tr><td rowspan="7">Hard</td><td>Set-up time reduction</td><td>SMED</td></tr><tr><td>Just-in-time delivery by suppliers</td><td>Kanban, Just In Sequence (JIS) &amp; Junjo Sequence</td></tr><tr><td>Equipment layout for continuous flow</td><td>VSM, Spaghetti chart, 5S, Yamazumi chart, Cell-design, Chaku-chaku</td></tr><tr><td>Kanban</td><td>Heijunka box, Kanban &amp; Milk run, Water spider &amp; Mizusumashi</td></tr><tr><td>Statistical process control</td><td>Jidoka, Ishikawa, Andon, Kamishibai, Poka-Yoke</td></tr><tr><td>Autonomous maintenance</td><td>TPM</td></tr><tr><td>Small group problem solving</td><td>Brain storming, 5 whys, Genchi Genbutsu, A3 sheets</td></tr><tr><td rowspan="7">Soft</td><td>Training employees</td><td>Job enlargement, Job enrichment, Coaching kata, OPL</td></tr><tr><td>Top management leadership</td><td>Hoshin Kanri, Walk the floor (Genchi Genbutsu), Challenge, Teamwork (Scrum meeting), Respect, Kaizen mind</td></tr><tr><td>Supplier partnership</td><td>Trust, Open communication, Close interaction (involvement)</td></tr><tr><td>Customer involvement</td><td>Gemba walking, Stand-up meetings, Obeya room, Catchball approach</td></tr><tr><td>Continuous improvement</td><td>PDCA/SDCA, «Make it ugly» (Kintsugi), Hansei, Shu-Ha-Ri</td></tr></tbody></table>

## 3.3 Human Factors

Whenever an attempt is made to implement a Lean approach within a company, putting the focus on human factors involvement and motivation is almost imperative [18]. The sole application of Lean tools, without considering the role of people in delivering value to customers, is indeed not enough for organisations to achieve a proper conversion that traces a Lean logic [19].

Existent literature defines human factors as “*all physical, psychological, and social characteristics of the humans, which influence the action in sociotechnical systems*” [20]. In order to get an overall picture of how human factors from the Industry 4.0, production and logistics areas can influence work tasks, a list of 27 human factors, belonging respectively to the physical, cognitive and organisational areas, was identified [21].
<table><caption>**Table 2.** List of physical, cognitive and organisational human factors [21]</caption><thead><tr><th>Category</th><th>Human Factor</th></tr></thead><tbody><tr><td rowspan="8">Physical</td><td>Working postures</td></tr><tr><td>Materials handling</td></tr><tr><td>Repetitive movements</td></tr><tr><td>Workplace layout</td></tr><tr><td>Risk of accident</td></tr><tr><td>Fitness for duty</td></tr><tr><td>Reactivity</td></tr><tr><td>Perception</td></tr><tr><td>Available time / Rapidity / Time pressure</td></tr><tr><td rowspan="7">Cognitive</td><td>Memory</td></tr><tr><td>Decision-making</td></tr><tr><td>Complexity (reasoning and parallel tasks)</td></tr><tr><td>Skilled performance / Experience</td></tr><tr><td>Human error probability</td></tr><tr><td>Work stress</td></tr><tr><td>Training</td></tr><tr><td rowspan="8">Organisational</td><td>Policies</td></tr><tr><td>Processes formalisation</td></tr><tr><td>Communication</td></tr><tr><td>Crew resource management / Leadership</td></tr><tr><td>Teamwork</td></tr><tr><td>Proactivity</td></tr><tr><td>Self-management</td></tr><tr><td>Telework</td></tr></tbody></table>

## 4 Discussion

Based on evidence put forward in current literature and the wealth of experience possessed by the three researchers participating in the project on the LM subject, three relationship maps were created. Each map was drafted for a specific neurodiversity (autism, ADHD and dyslexia), to give a proper illustration of how LM practices exert influence on the physical, cognitive and organisational human factors referring to neurodiverse workers.

During the assessment phase, the impact of each single “LM Tool” was considered among the entire list of human factors available. A score of +1 was assigned in case of positive effect of the LM tool on the considered human factor, -1 for all the circumstances where some kind of disadvantages were instead showing, and 0 whenever there
were both pros and cons to the implementation of the considered technique. For all the other cases where no meaningful effects were feasible, no score was given.

The results have then been grouped according to the categorisation previously described in Tables 1 and 2.

Tables 3, 4 and 5 report, for each relation, the number of interactions found between the “LM Practice” and the HF (human factor) of interest, as well as the overall evaluation about the impact of such tools, being positive or negative, the latter reported in brackets across the different tables.

<table><caption>**Table 3.** Impact of LM tools on human factors (HF) - Autism<fnref n="1" /></caption><thead><tr><th>LM Practices</th><th>Physical HF</th><th>Cognitive HF</th><th>Organisational HF</th></tr></thead><tbody><tr><td>Set-up time reduction</td><td>2 (---)</td><td>/</td><td>/</td></tr><tr><td>Just-in-time delivery by suppliers</td><td>2 (---)</td><td>5 (++)</td><td>2 (+++)</td></tr><tr><td>Equipment layout for continuous flow</td><td>8 (+++)</td><td>8 (++)</td><td>1 (=)</td></tr><tr><td>Kanban</td><td>/</td><td>3 (+++)</td><td>2 (+++)</td></tr><tr><td>Statistical process control</td><td>12 (+++)</td><td>7 (+++)</td><td>4 (+++)</td></tr><tr><td>Autonomous maintenance</td><td>2 (+++)</td><td>/</td><td>/</td></tr><tr><td>Small group problem solving</td><td>1 (---)</td><td>5 (---)</td><td>3 (---)</td></tr><tr><td>Training employees</td><td>2 (---)</td><td>5 (+)</td><td>/</td></tr><tr><td>Top management leadership</td><td>1 (---)</td><td>3 (---)</td><td>1 (---)</td></tr><tr><td>Supplier partnership</td><td>/</td><td>/</td><td>/</td></tr><tr><td>Customer involvement</td><td>1 (---)</td><td>5 (---)</td><td>3 (---)</td></tr><tr><td>Continuous improvement</td><td>/</td><td>3 (+)</td><td>/</td></tr></tbody></table>

With regard to autism, cognitive HFs are the most affected by LM Practices (44 total interactions) corresponding, though, to an unremarkable overall benefit. Physical HFs are, in fact, the ones receiving most of the benefits from a LM implementation program. Speaking of “LM Practices”, instead, “Statistical Process Control” tools overall show the highest influence, both in terms of number of relations found and efficacy; meanwhile “Supplier partnership”, “Set-up time reduction” and “Customer involvement” show the lowest efficacy, whether in terms of relations found or negative impact.

<table><caption>**Table 4.** Impact of LM tools on human factors (HF) – ADHD<fnref n="1" /></caption><thead><tr><th>LM Practices</th><th>Physical HF</th><th>Cognitive HF</th><th>Organisational HF</th></tr></thead><tbody><tr><td>Set-up time reduction</td><td>2 (---)</td><td>/</td><td>/</td></tr><tr><td>Just-in-time delivery by suppliers</td><td>2 (---)</td><td>5 (+)</td><td>2 (=)</td></tr><tr><td>Equipment layout for continuous flow</td><td>8 (=)</td><td>8 (---)</td><td>1 (+++)</td></tr></tbody></table>

<footnote n="1">¹ Legend: (+ + +) and (---) for “strong positive or negative feedback”; (+ +) and (---) for “mild positive or negative feedback”; (+) and (---) for “slight positive or negative feedback”; (=) for “neutral feedback”; / for “no interaction”</footnote>
<table><tr><td>Kanban</td><td>/</td><td>3 (+++)</td><td>2 (=)</td></tr><tr><td>Statistical process control</td><td>12 (++)</td><td>7 (+++)</td><td>3 (+++)</td></tr><tr><td>Autonomous maintenance</td><td>2 (---)</td><td>/</td><td>/</td></tr><tr><td>Small group problem solving</td><td>1 (+++)</td><td>5 (+++)</td><td>3 (+++)</td></tr><tr><td>Training employees</td><td>2 (+++)</td><td>5 (+)</td><td>/</td></tr><tr><td>Top management leadership</td><td>1 (+++)</td><td>3 (+++)</td><td>1 (+++)</td></tr><tr><td>Supplier partnership</td><td>/</td><td>/</td><td>/</td></tr><tr><td>Customer involvement</td><td>1 (+++)</td><td>5 (+++)</td><td>3 (+++)</td></tr><tr><td>Continuous improvement</td><td>/</td><td>3 (-)</td><td>/</td></tr></table>

In terms of ADHD, cognitive HFs still present the highest number of interactions (44) but, this time, organizational HFs are, overall, the mostly positive influenced by such tools. Referring to Lean practices, “Statistical Process Control” tools still affect neuro-diverse workers to the greater extent (22), even though the realms of the most beneficial LM tools belong to “Small group problem solving” and “Customer involvement” categories. “Supplier partnership” practices do not affect HFs of people affected by ADHD, while “Set-up time reduction” and “Autonomous maintenance” ones bring the most disadvantages to these people.

<table><caption>**Table 5.** Impact of LM tools on human factors (HF) – Dyslexia<fnref n="1" /></caption><thead><tr><th>LM Practices</th><th>Physical HF</th><th>Cognitive HF</th><th>Organisational HF</th></tr></thead><tbody><tr><td>Set-up time reduction</td><td>2 (---)</td><td>/</td><td>/</td></tr><tr><td>Just-in-time delivery by suppliers</td><td>2 (---)</td><td>5 (+)</td><td>2 (=)</td></tr><tr><td>Equipment layout for continuous flow</td><td>/</td><td>2 (+++)</td><td>1 (+++)</td></tr><tr><td>Kanban</td><td>/</td><td>3 (+++)</td><td>2 (=)</td></tr><tr><td>Statistical process control</td><td>5 (+++)</td><td>6 (+++)</td><td>4 (+++)</td></tr><tr><td>Autonomous maintenance</td><td>/</td><td>/</td><td>/</td></tr><tr><td>Small group problem solving</td><td>1 (---)</td><td>5 (---)</td><td>3 (+++)</td></tr><tr><td>Training employees</td><td>/</td><td>3 (+++)</td><td>/</td></tr><tr><td>Top management leadership</td><td>1 (---)</td><td>3 (---)</td><td>1 (+++)</td></tr><tr><td>Supplier partnership</td><td>/</td><td>/</td><td>/</td></tr><tr><td>Customer involvement</td><td>1 (---)</td><td>5 (---)</td><td>3 (+++)</td></tr><tr><td>Continuous improvement</td><td>/</td><td>3 (+++)</td><td>/</td></tr></tbody></table>

Similarly to what has been said for ADHD, even for dyslexia, cognitive HFs have the highest number of interactions (35), just like organizational HFs are, overall, the mostly positive influenced by such tools. “Autonomous maintenance” practices, especially in

<footnote n="1">¹ Legend: (+ + +) and (---) for “strong positive or negative feedback”; (+ +) and (---) for “mild positive or negative feedback”; (+) and (---) for “slight positive or negative feedback”; (=) for “neutral feedback”; / for “no interaction”</footnote>
the form of Total Productive Maintenance (TPM), do not affect dyslexic people in any
way, meanwhile “Set-up time reduction” techniques are the worst impacting. On the
other hand, “Statistical process control” are the most influential (15) as well as the most
beneficial tools.

5 Conclusion

The relationship charts provided throughout the paper provide insights on how Lean Manufacturing practices may play a role in supporting neurodiverse individuals on the workplace, a topic that has not been covered yet in current literature. It is evident, from the results of the research, that not all Lean tools have a beneficial effect among the entire range of human factors detected but are rather effective in dependence to the specific neurodiversity. Autism, ADHD and dyslexia have, in fact, different clinical manifestation on people suffering from these conditions and, consequently, they require a different treatment on the workplace.

Still, although the relationship charts may provide a useful insight on how a more ac-
commodating working environment can be created for neurodiverse people, it is im-
portant to consider that results have only been validated by a Lean expert, with a deep
theoretical and practical knowledge, but limited to this only topic. A need for a further
validation, provided this time by an expert in the field of neurodiversity, is therefore
required, as well as a final assessment on the workplace to definitively consolidate the
relations found.

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