Human Systems Integration (HSI)

Humanproof’s primary objectives are to influence system design, starting at the earliest phase of acquisition, and to ensure that the resulting system has the highest possible level of human performance with the fewest number of errors. This is what we mean by “humanproof,” which is accomplished by determining human capabilities and limitations through studies and analyses carried out within the following eight Human Systems Integration (HSI) domains:

  1. Manpower
  2. Personnel
  3. Training
  4. Human Factors Engineering
  5. Environment, Safety, and Occupational Health
  6. Habitability
  7. Personnel Survivability

The domains can be sub-divided into two categories based on objectives: Manpower, Personnel, and Training are considered Manpower Objectives, while Human Factors Engineering, Environment, Safety, and Occupational Health, Habitability, and Personnel Survivability are regarded as Capability Objectives.  Manpower Objectives concern what many organizations refer to as “Human Resources,” while Capability Objectives are concerned with the mission effectiveness of those resources.  Tests and Evaluations can focus on either Manpower or Capability Objectives.

It is prudent to include HSI representatives as subject matter experts on other teams, such as systems engineering, design, quality assurance, and others responsible for human-oriented acquisition, design, and construction activities.

Major general objectives of HSI activities include, but are not limited to:

  • Defining HSI requirements early in system acquisition
  • Optimizing Manning to meet defined objectives
  • Identifying the roles of humans in system operations and maintenance
  • Improving training and personnel management
  • Identifying human performance lessons learned in baseline comparison systems
  • Applying simulation and prototyping early in development
  • Applying human-centered design
  • Verifying and optimizing usability
  • Enhancing situational awareness and decision making
  • Reducing the incidence and impact of human errors
  • Enhancing space habitability and quality of life
  • Enhancing the maintainability of equipment
  • Reducing accidents and mishaps
  • Applying human-centered test and evaluation
  • Assessing task-work, teamwork, and organizational effectiveness

Each HSI domain is briefly described below:


Manpower addresses the number, type of personnel, and required specialties needed to train, operate, maintain, and support a deployed system. Manpower requirements are based on the range of operations that will be performed and must consider both continuous, sustained operations and high-demand situations.  Manpower requirements are based on task analyses conducted during the functional allocation process and consider all relevant factors, including fatigue; cognitive, physical, sensory overload; environmental conditions (e.g., heat/cold), and reduced visibility. Since Manpower is often a major determinant of cost over the system’s life-cycle, engineering designs should optimize the efficient and economic use of manpower, and keep human resource costs manageable. Manpower should be considered in conjunction with personnel capabilities, training, and human factors engineering because, when fully integrated, these functions maximize overall system effectiveness and efficiency.


Personnel addresses the type of human knowledge, skills, abilities (KSAs), physical characteristics, experience, and aptitudes required to operate, maintain, and support a system and also to lead, direct, and supervise these functions.  Along with Manpower, the availability of personnel and their KSAs should be identified by Personnel Analysts early in the acquisition process.  They should also address the means to recruit and retain people needed for key positions.  Personnel characteristics impact Manpower and Training. During functional analysis and allocation, the goal is to ensure compatibility, interoperability, and integration of all functional and physical interfaces.


Training is the learning process allowing personnel, individually or collectively, to acquire or enhance pre-determined job-relevant knowledge, skills, and abilities, by developing necessary cognitive, physical, sensory, and team dynamic abilities. The “training/instructional system” integrates training concepts and strategies, along with elements of logistic support to satisfy personnel performance levels required to operate, maintain, and support the systems.  This includes the “tools” used to provide learning experiences, such as computer-based interactive courseware, simulators, and actual equipment, job performance aids, and Interactive Electronic Technical Manuals. The focus is on developing and testing Instructor Led Training (ILT) and Interactive Multimedia Instruction (IMI) included in the acquisition, and documenting life-cycle changes to training strategy, plans, policy, and procedures necessary to support introduction of the new system.

Human Factors Engineering

Human factors are the end-user cognitive, physical, sensory, and team capabilities required to perform system operational, maintenance, and support tasks. Human factors engineers contribute to the acquisition process by providing for the effective utilization of personnel.  This is accomplished by designing systems that capitalize on and do not exceed the abilities of the user population. The human factors engineering team works to integrate human characteristics of the user population into system definition, design, development, and evaluation processes  in order to optimize human-machine performance, maximize usability, and overall sustainment of the system.

Human factors engineers focus on designing such human-machine interfaces as the following:

  • Functions and tasks, and allocation of functions to human performance or automation;Information and characteristics of information that provide the human with the knowledge, understanding and awareness of what is happening in both the tactical environment and in the system;
  • The natural and artificial environments, environmental controls, and facility design;
  • Provisions for team performance, cooperation, collaboration, and communication among team members and with other personnel;
  • Job design, management structure, command authority, policies and regulations impacting behavior;
  • Aspects of a system supporting successful operation of the system, such as procedures, documentation, workloads, and job aids;
  • Decision rules, decision support systems, provision for maintaining situational awareness, mental  models of the tactical environment, provisions for knowledge generation, cognitive skills and attitudes,memory aids; and,
  • Hardware and software elements designed to enable and facilitate effective and safe human performance, such as controls, displays, panels, workstations, worksites, accesses, labels and markings, structures, steps and ladders, handholds, maintenance provisions, etc.

Environment, Safety, and Occupational Health

The environment is the external context within which the system under design and development will function. Environmental Engineers work with the customer, team leads, subject matter experts, and others to assess and prioritize environmental concerns associated with the system being developed or changed. They ensure that environmental issues are addressed across the entire program, prioritizes these concerns, and that a process for mitigating them is established and maintained.

Safety and Occupational Health focuses on identifying potential risks to people responsible for operating the system. System Safety Engineers accomplish this by conducting hazard analyses associated with system development, design, construction, operation, and disposal, and by establishing processes and procedures based on established guidelines for mitigating identified hazards.


Habitability factors are those living and working conditions necessary to sustain the morale, safety, health, and comfort of the user population. They directly contribute to personnel effectiveness and mission accomplishment, and often preclude recruitment and retention problems. Some examples are lighting, space, ventilation, and sanitation; noise and temperature control (i.e., heating and air conditioning); religious, medical, and food services availability; and berthing, bathing, and personal hygiene.

Habitability Analysts establish requirements for:

  • The physical environment within which personnel will function,
  • Personal services, and
  • Living or working conditions that have a direct impact on meeting or sustaining identified performance requirements, sustaining mission effectiveness, or undermine employee recruitment or retention.

Personnel Survivability

Personnel Survivability addresses design features of the total system that reduce susceptibility of operators/users, maintainers and logistics personnel to injury, operational degradation, or failure. Personnel Survivability issues should be considered in the context of the full operational spectrum, including the perspective of personnel who come in contact with the system. Personnel Survivability Analysts determine the range of personnel survivability hazards, and then develop mitigation strategies to address issues identified.

HSI Tests and Evaluations

Since the primary objective of HSI is to influence system design and usability, in order that the resulting system will have the highest possible level of human performance at the lowest possible total cost, a systematic program of Tests and Evaluations should be conducted across all systems including a human-machine interface.  Based upon program scope and customer requirements, this may include Developmental Tests and Evaluations (DT&E), Operational Tests and Evaluations (OT&E) and/or Usability Assessments (UA). Potential test events are identified and prioritized.  For each test selected, specific objectives are established, along with test conditions, metrics, and performance standards. Test event execution includes writing a Test Plan, executing the test, followed by writing a Quick Look and Final Test Report summarizing findings and making recommendations for design, operational, or usability change, as appropriate.