An Overview of the Most Crucial Step in Combination Product Development, the Design Control Process


Your team has an idea for a combination product with greater efficiency and stronger efficacy than similar products currently available. You believe this game-changing product will revolutionize the marketplace.  But you’re just starting out, and the journey from idea to commercial product is long and winding. Where do you begin?

The short answer: right where you are. 

From there, you can create a plan for a framework called the Design Control Process, which is the most crucial step in developing a combination product and bringing it to market.

The Design Control Process is the set of tasks followed by a development team to ensure that a device meets the needs of the user, the intended use, and is both safe and effective. This process helps improve product safety, user satisfaction, maintains regulatory compliance, as well as minimizes the number of recalls. The Design Control Process relies on detailed record keeping and risk assessments, which can be used in an US Food and Drug Administration (FDA) evaluation. Design controls follow typically have the following subtasks: Design and Development, Design Inputs and Outputs, Design Verification and Validation, and Design Transfer

“At their most basic level, regulations require that manufacturers: 

  • Clearly state what they intend to produce (Planning and Design Inputs)
  • Develop a design that meets those needs (Design Outputs and Design Review)
  • Confirm that the design meets the original intent (Verification)
  • Confirm that manufactured product can be produced reliably and achieve the desired result (Transfer and Validation)    
  • Maintain records of key development activities and decisions (Design Changes and Design History File)”

 – MEDIcep

Design and Development

The importance of planning in design control can’t be emphasized enough. When bringing an idea to life, every aspect of the development process must be considered to ensure safety, address all necessary specifications, and guarantee that user needs are met.

Here is a closer look at different types of plans for the Design Control Process:

  • Design and Development Plan (DDP) – Provides a master plan for the product and includes an overview of the activities involved in the development process, those individuals/departments responsible for the activities, and the resources needed to complete each activity. A DDP is a living document that’s frequently updated and revisited throughout product development.
  • Risk Management Plan (RMP) – Describes the scope of activities carried out to mitigate any potential risks (e.g., hazards, harms) that could result from using the product as well as the responsibilities and authorities of the development team and the criteria for risk acceptability. A RMP is also intended to be referenced and revisited throughout the life cycle of a product.  
  • Human Factors (HF) Plan – Considers how users interact with every component of the product, from the physical device to any associated software, user manuals, and more and includes the user interface design. The goal when creating a HF Plan is to use the information you glean from user feedback to minimize use errors and use-associated risks.

Design Inputs and Outputs

Design inputs are the specifications for your product that are based on user needs. These inputs are very precise and outline the most important parameters that the product needs to meet, such as the product’s functions, performance, safety, reliability, maintenance, and more.

Design outputs are, as the name implies, the products of design inputs. Design outputs document exactly what is needed to design the product to meet the user needs and specifications (inputs). Design outputs utilize data, drawings, schematics, and other means to illustrate details of the product design process.

The International Standard for Organization (ISO 13485:2014 7.3.3) outlines requirements for outputs.


“Outputs shall: a) meet the input requirements for design and development, b) provide appropriate information for purchasing, production, and for service provision, c) contain or reference product acceptance criteria, and d) specify the characteristics of the product that are essential for its safe and proper use. The design output should include every physical and numerical aspect of the design and should be recorded in the Device Master Record.”

ISO 13485:2014 7.3.3


In the Design Control Process, each design input is converted into a new design output that is then verified as acting in accordance with its input. This design output then becomes the input for another step in the design process. This process is illustrated below in what is known as a “waterfall diagram.”

Figure 1. Diagram of the Design Control Process. Source: May-Newman, Karen & Cornwall, PhD, PEng, G. Bryan. (2012). Teaching medical device design using design control. Expert review of medical devices. 9. 7-14. 10.1586/erd.11.63.


Verification and Validation

In addition to designing and developing a product, you must verify and validate the product works as intended. Design Verification and Design Validation are essential to the Design Control process, but before discussing the process for each, let’s consider how they differ. 

The FDA states: “Design verification is confirmation by objective evidence that design output meets design input [‘I made the product correctly’]. Design validation means establishing by objective evidence that specifications (specified requirements) conform with user needs and intended use(s) [‘I made the correct product’].” 

These subtle but important differences need to be kept in mind during the Design Control Process. 


Verification Planning and Reporting

Planning for verification begins early in the Design Control Process and continues throughout a product’s life cycle. When developers decide on an input, it’s important that they also determine how they’ll verify that its eventual output meets the required specifications.

In other words, you must decide which tests, inspections, or analyses to use to specifically measure the outputs and establish the procedures early in the process to minimize risks and costs of having to change components or design features later in the process. A Design Verification Plan is a living document that can evolve, as design inputs change, verification testing and analyses can change too.

Project leaders must document every adjustment in the Design Verification Plan and Report, which provides a summary of the testing procedures used to verify the design. Results for each analysis as well as any design modifications that resulted from testing must be documented.

In addition, the users themselves must be considered in the assessment of product usability. Human Factors studies analyze usability of the product, or how users interact with a product. These studies are an essential part of Design Verification.


HF Formative and Summative Analyses

Formative and summative analyses offer insights into the viability of a design. While these two assessments are different approaches to measuring usability, they’re two sides of the same coin.

Formative analysis helps developers in the earliest stages of design determine what works and what doesn’t work with a given model. The analysis involves a small group of users who provide feedback on their experience with the product and assist developers in improving the overall user experience. 

Summative analysis requires a larger number of participants and takes place when a product has already launched. The goal of a summative study is to demonstrate that the final product design meets the users’ needs and, furthermore, that the use-related risks have been appropriately mitigated. The collected data provide useful input for revisiting designs and improving usability.


Validation Planning and Reporting

Design validation is used to determine whether the product truly meets the needs of the user and the demands of the market. Validation planning should happen early in the design process. At the beginning of the design process, the development team needs to determine which procedures are necessary to validate the design, how will risk analysis be quantified, and who on the team will address these individual needs. 

The development team should record all verification and validation procedures and results in the Design History File (DHF) along with any other records throughout the Design Control Process.


Design Transfer

Design transfer begins the official handover of the product design from the developer to the manufacturer. Developers need to define the activities and deliverables necessary for the transfer of the design and the ability of the manufacturer to support commercial production successfully.

Ensuring a suitable and sustainable manufacturing process requires the following:

  • Process Validation – Beyond design validation, process validation requires reviewing the production process to determine whether the results are consistent across every batch, and if not, making the necessary changes. Verification tests the production process and continues testing to be sure the manufactured product continually meets the specifications.   
  • Device Master Record – A compilation of instructions, drawings, and other documentation needed for production. The master record keeps all the details organized and on hand.
  • Risk Management – Continue to revisit the risk management plan as noted above to minimize risk for the product’s life cycle.
  • Design History File – When the product has gone through the entire process from early design to production, the Design History File should accurately reflect all iterations, processes, and procedures throughout the product’s history.

The Design Control Process is the most crucial step in combination product development because implementing this process results in a safe and effective product that meets user needs, intended use, and specifications. After completing the Design Control Process, your game-changing combination product is significantly closer to being ready for the market and a successful FDA review.