Process Identification and the Turtle Diagram — A Complete Toolbox from the ISO 9001 Process Approach to On-Site Implementation

1. Introduction: Why the Process Approach Always Looks Good but Fails to Implement

The ISO 9001:2015 standard establishes the "process approach" as one of the core principles of the quality management system (QMS), explicitly requiring organizations to "determine the processes needed for the QMS and their application throughout the organization." However, in my experience of providing quality system guidance to over forty manufacturing and service companies over the past decade, one recurring issue stands out: companies can articulate the "process approach," but at the execution level, eight out of ten cannot clearly explain what their processes are, how they are managed, and who is responsible.

The most common dilemmas are threefold:

First: The process list is "copied." Consulting firms provide a standardized process list, which companies then tweak and use. When auditors ask, "What is the input for this process?" the on-site personnel are stumped—though it was written in the PPT, no one actually follows it.

Second: Processes and departments are at odds. A cross-departmental process is mapped out with swim lanes, but each department only recognizes its own "patch of land," with no one accountable for the end-to-end process performance. The process is there, but the process owner is missing.

Third: Processes and documents are disconnected. Twenty turtle diagrams are drawn and look great on the wall, but the operators do not understand how the turtle diagrams relate to them. The processes in the system documents and actual operations are two different sets of logic.

The root of these issues lies in the same place: the step of process identification has not been solidified. Process identification is the "foundation" of the process approach—without a solid foundation, all subsequent work (process performance, process audit, process improvement) is like building a castle in the air.

This article will start from the methodology of process identification, systematically explaining the principles, drawing methods, and practical applications of the turtle diagram (Turtle Diagram), to help quality management practitioners truly implement the process approach from "paper" to "practice."

2. Process Identification — The First and Most Important Step of the Process Approach

2.1 What is a "Process"? Clarify the Concept First

Before discussing process identification, it is necessary to align our understanding of the basic concept of "process."

ISO 9000:2015 defines a process as: "a set of interrelated or interacting activities that use inputs to deliver an output."

This definition may seem simple, but it contains three key elements:

1. Processes must have inputs and outputs. Without inputs, a process has no "raw materials"; without outputs, a process has no "product."
2. Processes consist of a series of activities. These activities are interrelated or interacting—not isolated actions.
3. The essence of a process is "transformation." Inputs are transformed into outputs within the process, adding new value.

To understand this intuitively, consider the example of cooking a dish:

When this logic is scaled up to an organization's QMS, any identified process can be described using the same framework—this is the core concept of the turtle diagram.

2.2 Four Levels of Process Identification

Within the framework of the ISO 9001 system, process identification is divided into four levels, gradually expanding from macro to micro:

Level 1: System-Level Process Identification. Answer the question, "What processes are needed for the QMS?" Typically, 4-6 major process groups are identified based on the PDCA cycle and standard requirements (e.g., planning processes, resource management processes, product realization processes, measurement, analysis, and improvement processes). The result of this level is a process list.

Level 2: Process Group-Level Identification. Under each major process group, identify specific sub-processes. For example, the "product realization process" can be broken down into: contract review process, design and development process, procurement process, production and service provision process, inspection and testing process, etc. The result of this level is a process relationship diagram.

Level 3: Individual Process Identification. For each specific process, use the turtle diagram or SIPOC tool to detail its six elements (see below). The result of this level is a process turtle diagram.

Level 4: Activity-Level Identification. Within the process, further refine to specific activities and operational steps, forming procedure documents, work instructions, and forms. The result of this level is documented information.

Many companies, when building their systems, jump directly from Level 1 to Level 4—listing process lists and then diving into writing documents. The absence of Levels 2 and 3 is the fundamental reason for the disconnect between processes and documents.

2.3 The "Six Questions" Method for Process Identification

In actual guidance, I use a simple method to help companies complete Level 3 process identification: the Six Questions Method.

Facing any candidate process, ask yourself six questions:

1. What is the purpose of this process? (Why is this process needed? Who does it create value for?)
2. What are the inputs for the process? Where do they come from? (Who is the upstream? What is the form of the input?)
3. What are the outputs of the process? Where do they go? (Who is the recipient? How are the outputs used?)
4. What resources are needed for the process? (Personnel, equipment, facilities, systems, environment, etc.)
5. What criteria control the process? (Standards, norms, regulations, procedures, acceptance criteria, etc.)
6. What are the key performance indicators for the process? (How is the process effectiveness measured?)

Organizing the answers to these six questions on a single diagram yields a standard turtle diagram.

3. Comprehensive Analysis of the Turtle Diagram — Principles, Structure, and Drawing Methods

3.1 Why is it Called a "Turtle Diagram"?

The turtle diagram (Turtle Diagram) is named for its shape—the core activities of the process are in the "turtle body" position, with the four "turtle legs" representing inputs, outputs, resources, and criteria. The head and tail can extend to performance indicators and improvement opportunities. Overall, it looks like a turtle, hence the name.

This tool was introduced by the ISO/TC 176 technical committee during the promotion of ISO 9001:2000 and has been in use for over two decades. Its core value lies in: using a standardized two-dimensional framework to visually and structurally present all key elements of a process, making it clear to anyone what the process is, how it is done, who does it, and how well it is done.

3.2 Standard Structure of the Turtle Diagram

A complete turtle diagram includes the following six core elements:

┌─────────────────────────────────────────────────────────────┐
│                    4. What methods are used? (Resources/Equipment)                │
│              Personnel, equipment, systems, facilities, environment, etc.                     │
├─────────┬─────────────────────────────────────┬─────────────┤
│ 1. Input │                                     │ 2. Output    │
│ From where │         3. Core Activities              │ To where │
│ Input specifications │        (What is done? Who does it?)            │ Output specifications  │
│ Upstream delivery │                                     │ Downstream receipt  │
├─────────┴─────────────────────────────────────┴─────────────┤
│                    5. What criteria are followed? (Methods/Standards)               │
│              Procedures, norms, standards, regulations, acceptance criteria, etc.                 │
├─────────────────────────────────────────────────────────────┤
│                6. How is it evaluated? (Performance Indicators)                        │
│            Efficiency, effectiveness, compliance, timeliness, etc. KPIs                      │
└─────────────────────────────────────────────────────────────┘

Detailed Explanation of Each Element:

Element 1—Input (Input): Conditions that exist before the process begins. This includes, but is not limited to, materials, data, documents, outputs from the previous process, customer requirements, etc. When describing inputs, specify: what they are, from which upstream process they come, and what the quality standards are.

Element 2—Output (Output): The results produced after the process ends. This includes, but is not limited to, products, reports, decisions, data, services, inputs for the next process, etc. When describing outputs, specify: what they are, to which downstream process they are delivered, and what the acceptance standards are.

Element 3—Core Activities (Core Activities): The specific activities that transform inputs into outputs. This is the "turtle body" of the turtle diagram and the essence of the process. When describing activities, specify: activity name, executor, key steps, and the flow relationship between activities.

Element 4—Resources (Resources/How): The supporting conditions required to execute the process activities. This includes: personnel (skill requirements, qualification requirements), equipment (equipment type, precision requirements), systems (software systems, information systems), facilities (locations, tooling), environment (temperature and humidity, cleanliness), etc.

Element 5—Criteria (Criteria/Standards): The rules that guide and control the process activities. This includes: procedure documents, work instructions, process specifications, laws and regulations, industry standards, technical specifications provided by customers, etc.

Element 6—Performance Indicators (Performance Indicators): Metrics used to measure whether the process is operating effectively. These are typically divided into effectiveness indicators (output quality) and efficiency indicators (output speed/cost). Each process should have at least one to two key performance indicators.

3.3 Seven-Step Method for Drawing a Turtle Diagram

In practical operations, I recommend following these seven steps to draw a turtle diagram:

Step 1: Define the boundaries and purpose of the process. Clearly identify where the process starts and ends. For example, the starting point of the "procurement process" could be "receiving a procurement request," and the endpoint could be "material warehousing and inspection." Unclear boundaries will lead to a messy turtle diagram.

Step 2: List core activities. In the "turtle body" position, use 3-5 verb phrases to describe the most critical activities in the process. For example, the activities in the procurement process could be: supplier selection → order placement → delivery tracking → incoming inspection → warehousing and settlement. The number of activities should not exceed seven, otherwise, it indicates that the process boundaries are set incorrectly.

Step 3: Identify inputs and outputs. Inputs are what exist before the process begins, and outputs are what are produced after the process ends. Use the "from XX to XX" mindset to confirm the upstream and downstream relationships.

Step 4: List required resources and equipment. This step often overlooks "soft resources"—information systems, training, experience, etc. Especially for personnel capability requirements, many companies only write "operator" on the turtle diagram, but specifying "trained and qualified after certain training" is more useful.

Step 5: List applicable criteria and standards. This includes external criteria (laws, standard clauses, customer requirements) and internal criteria (procedure documents, management systems, work instructions). This step helps companies quickly identify gaps in their document system—if a process lacks corresponding procedures or specifications, it indicates a lack of documented coverage.

Step 6: Define performance indicators. Set at least 1-2 indicators for each process. The selection of indicators should follow the SMART principle: specific (Specific), measurable (Measurable), achievable (Achievable), relevant (Relevant), and time-bound (Time-bound).

Step 7: Review and validate. After the turtle diagram is completed, it must be reviewed by the actual process executors (operators, team leaders) and the process owner (department manager or designated responsible person). The review standard is simple: Can the process be smoothly executed according to the turtle diagram? If the answer is no, the diagram needs to be revised.

3.4 Differences and Connections Between the Turtle Diagram and SIPOC

In actual work, many quality practitioners confuse the turtle diagram with SIPOC (Supplier-Input-Process-Output-Customer). While these tools are similar, they have different focuses:

Suggested Usage Order: Start with SIPOC to outline the entire process (who the supplier is, what the input is, what the process does, what the output is, who the customer is), and then use the turtle diagram to delve into the internal operational logic of each process. SIPOC is the "telescope," and the turtle diagram is the "microscope."

4. Practical Applications of the Turtle Diagram — Three Typical Scenarios

4.1 Scenario One: Process Clarification During the Establishment of a New System

A certain electronics manufacturing company (referred to as "Jingyuan Electronics," a pseudonym) was implementing the ISO 9001:2015 system, and the team was completely lost about "which processes need to be identified." The consulting firm provided a general process list, but the management felt that "this list does not align with our actual business."

I suggested they use the turtle diagram method to reverse-engineer the processes:

Step 1: Business activity reconstruction. Have each department write down all their daily work activities on sticky notes and post them on a whiteboard (without worrying about whether "this is a process as defined by the standard").

Step 2: Activity consolidation. According to the logic of "input → activity → output," consolidate similar activities into candidate processes, resulting in 27 candidate processes.

Step 3: Use the turtle diagram to screen. Draw a simplified turtle diagram (filling in only input, output, and core activities) for each candidate process to see if the inputs and outputs are clear and the activities are stable. Ultimately, they filtered out 17 processes that truly have "independent value" from the 27, and after consolidation, formally identified 12 system processes.

Step 4: Detailed turtle diagrams. For the 12 processes that passed the screening, complete the full turtle diagrams (filling in all six elements) and use them as the basis for writing procedure documents and work instructions.

Result: The document writing cycle was shortened from the expected three months to six weeks. Because in the process of drawing the turtle diagrams, the team had already discussed and clarified how the processes run, writing documents became a matter of translating the content of the turtle diagrams into text—no longer needing to "compile" documents, but only to "record" them.

4.2 Scenario Two: Process Review Before Annual Audit

A certain automotive parts company, "Hengchi Precision," undergoes IATF 16949 surveillance audits annually. Before each audit, the quality department often falls into a "last-minute cramming" state: supplementing documents, records, and signatures.

Before the 2025 annual audit, I suggested they change their approach—use the turtle diagram for process review. The specific method is:

In each process responsibility department, the process owner leads a 30-minute workshop involving executors to review the turtle diagram of the process according to the following steps:

1. Are the inputs and outputs still correct? Have upstream suppliers changed? Have downstream customer requirements been updated?
2. Have core activities changed? Have operational procedures been adjusted after the introduction of new equipment? Have responsibilities been re-distributed after new employee training?
3. Are the criteria documents and versions up-to-date? Have procedure documents been revised? Have the external standards referenced been updated?
4. Are resources sufficient? Is the equipment precision still within the required range? Are personnel qualifications still valid?
5. Are performance indicators met? If not, have improvements been initiated?

The results surprised the management team: in just one and a half days, all 12 processes were reviewed, and five process-level issues were identified and resolved—this included two cases where input sources had changed but the procedure documents had not been updated, and one case where the performance indicators for a process had not been calculated for three months.

On the day of the audit, the auditor asked a standard question: "Please describe your company's procurement process." The quality manager directly presented the turtle diagram of the procurement process and clearly explained the inputs, outputs, activities, resources, criteria, and indicators in two minutes—the auditor immediately praised it as an "exemplary application of the process approach."

4.3 Scenario Three: Problem Diagnosis for Cross-Departmental Processes

When a process has issues, the turtle diagram is also an excellent tool for problem diagnosis.

A certain medical device company (referred to as "RuiKang Medical," a pseudonym) has long had a problem with the "design change process" having an excessively long cycle—the average approval cycle for a design change is 47 days, while the industry benchmark is 15 days or less. Management believed this was due to "departmental buck-passing" and wanted to compress the cycle through administrative orders.

I reviewed the turtle diagram of the design change process and led the team in a detailed analysis:

Problems Identified by the Turtle Diagram:

Based on the turtle diagram diagnosis, the team formulated six improvement measures:

1. Standardize the design change request template and integrate it into the OA system.
2. Reduce the 9 approval nodes to 5, removing the 3 "notification" nodes and replacing them with automatic system notifications.
3. Define the distinction between "major changes" and "minor changes," with minor changes following a fast-track process.
4. Change review meetings to twice a week, with online reviews for special cases.
5. Refine the clauses of the design change management procedure, adding distribution and execution confirmation processes.
6. Add "average change cycle" and "first-time pass rate" to the performance indicators.

One month after the implementation of improvements, the average design change approval cycle was reduced from 47 days to 19 days; after three months, it stabilized at 12 days, surpassing the industry benchmark. The source of all improvement measures was just one turtle diagram.

5. Common Errors in Turtle Diagrams and How to Avoid Them

5.1 Error One: Treating the Turtle Diagram as a "Filling Task"

This is the most common issue. Many companies treat the turtle diagram as a task assigned to a clerk to fill out the template, leading to content that is disconnected from actual work.

Correction Method: The turtle diagram must be led by the process owner and drawn with the participation of process executors, with the quality department providing only template and method support. The process of drawing the turtle diagram itself is a process review—those who do not participate in the review cannot draw a good turtle diagram.

5.2 Error Two: Writing Inputs and Outputs as "Document Names"

Many turtle diagrams list document names as inputs (e.g., "purchase request form," "inspection report") and outputs (e.g., "warehousing form," "payment request"). Documents are carriers of information, but the process truly handles "materials and information"—the input should be "material list to be procured + material requirement information," not just the "purchase request form."

Correction Method: When describing inputs and outputs, distinguish between "carrier" and "content." For example, say "material requirement information carried by the purchase request form" instead of just "purchase request form."

5.3 Error Three: Core Activities Without Verbs

Some turtle diagrams describe core activities with noun phrases like "incoming inspection" or "supplier management," which do not convey "how it is done."

Correction Method: Core activities should be described using verbs. For example, "conduct incoming sampling inspection," "evaluate and select qualified suppliers," "track order delivery progress," etc.

5.4 Error Four: Performance Indicators Become a "Formality" for Audits

The most common situation is that each process's performance indicators are set to "100% compliance," which has no management significance. Or, indicators are set but never actually measured—performance indicators on the turtle diagram and those on the actual management dashboard are two different sets.

Correction Method: The achievability and measurability of indicators are more important than how they look. It is better to write "actual measurement of cycle time" (even if it is not ideal now) than to write "cycle time compliance rate 100%." The value of indicators lies in driving improvements, not in decorating system documents.

5.5 Error Five: Only Writing Position Names in the Resource Element

Many turtle diagrams list only position names (e.g., "inspector," "operator," "engineer") in the resource element, which is essentially useless—because when doing process identification, it is impossible not to know which positions are involved.

Correction Method: Add a "capability requirement" dimension to the personnel resources. For example, "inspector who has undergone XX training and passed the qualification, holding XX certification." This not only enhances the practicality of the turtle diagram but also provides input for the training system—if a process's personnel capability requirements do not have corresponding training courses, it indicates a gap in the training system.

6. Advanced Applications of the Turtle Diagram — From Single Processes to Process Networks

6.1 Interface Management Between Processes

A process often has more than one output, and these multiple outputs may flow to multiple downstream processes. Similarly, a process's inputs may come from multiple upstream processes. This is the core issue of process interface management.

While the turtle diagram does not directly show interfaces within a single process, it can indirectly manage interfaces through the description of "input sources" and "output destinations." A more advanced approach is:

1. Post all process turtle diagrams on the meeting room wall and connect them with arrows to show upstream and downstream relationships.
2. Identify all interface points and check if each interface meets the following three conditions:
   • Information Symmetry: The upstream knows what the downstream needs, and the downstream knows what the upstream can provide.
   • Consistent Standards: Both parties at the interface have the same definition of what is "qualified."
   • Feedback Loop: The downstream has an evaluation and feedback mechanism for the upstream output.

6.2 Process Maturity and Linking with the Turtle Diagram

Once a company has established a complete library of turtle diagrams, it can conduct process maturity assessments based on these diagrams. The assessment dimensions can follow the six elements of the turtle diagram:

Using this framework, companies can assess each process, identify the weakest elements, and develop targeted improvement plans.

7. Conclusion: The "Way" and "Technique" of a Turtle Diagram

The turtle diagram is a tool with a low entry barrier—anyone can learn to draw it in half an hour. However, truly using the turtle diagram effectively relies not on the "technique" level skills, but on a "way" level cognitive shift.

Technique Level: Learn the six elements of the turtle diagram, the seven-step method, and the format requirements. This is a skill that every quality practitioner can quickly master.

Way Level: Truly understand the management philosophy of the "process approach"—every task in the organization is not isolated but operates within an interconnected network of processes. Understanding this "way" transforms the turtle diagram from a form to check off during audits into a mirror that reflects management realities.

In the companies I have guided, teams that draw and use the turtle diagrams well often go through the following transformation process:

• Level 1: They feel the turtle diagram is "extra work that adds burden."
• Level 2: After drawing the turtle diagram, they realize "what was unclear before is now clear."
• Level 3: When encountering management issues, their first reaction is "to review the turtle diagram."
• Level 4: They naturally think in terms of process thinking without needing to draw the turtle diagram.

This transformation process from "able to draw" to "able to use" and then to "integrated into the bloodstream" is the best metaphor for the QMS moving from "existence" to "effectiveness."

The process approach is never an additional requirement imposed by ISO 9001 on companies—it simply writes down the principle that "good management should be this way." The turtle diagram is the most practical tool to help companies turn this principle from words into reality.

A well-drawn turtle diagram is a process that is understood; a process that is understood is a process that can be managed well.

Knowledge code: 2.2.1

Version: v20260726

Author: Quality Think Tank The Quality Think Tank is dedicated to providing systematic knowledge, methods, and practical tools to quality management practitioners, helping companies continuously improve their quality capabilities.