1.
Which items are kept current as an objective of the management engineering program (MEP)?
Correct Answer
C. Manpower standards and models
Explanation
Manpower standards and models are kept current as an objective of the management engineering program (MEP). This is because manpower standards and models are essential for effective management and planning of human resources in an organization. By keeping them current, the MEP ensures that the organization has accurate and up-to-date information about the required number of employees, their skills, and the time needed to complete tasks. This helps in optimizing workforce productivity, improving efficiency, and making informed decisions regarding manpower allocation and resource planning.
2.
Which management engineering program (MEP) tool is the Air Force's approved methodology for developing manpower quantification models?
Correct Answer
D. The Air Force manpower standard (AFMS)
Explanation
The Air Force manpower standard (AFMS) is the approved methodology for developing manpower quantification models in the management engineering program (MEP) tool. This tool is used by the Air Force to assess and determine the manpower requirements for various tasks and activities. The AFMS provides a standardized approach to accurately quantify and allocate manpower resources based on the specific needs of the Air Force. It ensures consistency and efficiency in manpower planning and management within the organization.
3.
You should consider using the management advisory study (MAS) methodology of the management engineering program (MEP) when you
Correct Answer
B. Need a short-term analysis to resolve an issue
Explanation
The management advisory study (MAS) methodology of the management engineering program (MEP) should be used when there is a need for a short-term analysis to resolve an issue. This methodology is designed to provide quick and efficient solutions to problems, making it suitable for addressing immediate concerns. It focuses on analyzing the current situation, identifying potential solutions, and implementing them in a timely manner. By using MAS, organizations can effectively address and resolve issues, ensuring smooth operations and minimizing any negative impacts.
4.
You should not consider using the management advisory study (MAS) methodology of the managaement engineering program (MEP) when
Correct Answer
D. You need a method to quantify manpower or man-hours for the purpose of programming future requirements
Explanation
The management advisory study (MAS) methodology of the management engineering program (MEP) should not be considered when there is a need to quantify manpower or man-hours for the purpose of programming future requirements. This suggests that the MAS methodology may not provide the necessary tools or techniques to accurately measure and forecast manpower needs.
5.
When determining the feasibility of a manpower study effort based on the decision questions, you, as the management engineer (ME) discover that the function will allow for ease of the follow-on phases such as measurement. Which consideration of the study effort are you assessing?
Correct Answer
D. Degree of Standardization
Explanation
The correct answer is Degree of Standardization. When assessing the feasibility of a manpower study effort, one consideration is the degree of standardization. This refers to the extent to which the function allows for ease of follow-on phases such as measurement. If the function is highly standardized, it means that there are established processes and procedures in place, making it easier to conduct the study and measure the results. This increases the feasibility of the effort.
6.
In the manpower engineering program (MEP), how can you capture manpower with an Air
Force manpower standard (AFMS) when you discover that only slight differences exist between input locations?
Correct Answer
A. Develop a variances
Explanation
To capture manpower with an Air Force manpower standard (AFMS) when there are only slight differences between input locations, developing a variances would be the appropriate approach. This means creating a system to account for and track any variations or deviations from the standard. By doing so, the slight differences can be accounted for and managed effectively, ensuring accurate manpower capture within the AFMS.
7.
Which consideration are you addressing during the feasibility phase of a manpower study effort, when you identify several unique Federal Aviation Administration directives that establish unique workload for your function under study?
Correct Answer
B. External mandates
Explanation
During the feasibility phase of a manpower study effort, considering external mandates is important when identifying unique Federal Aviation Administration directives that establish unique workload for the function under study. These external mandates are regulations or requirements imposed by the FAA that must be taken into account when determining the feasibility of the manpower study. Compliance with these mandates is crucial for the success of the study and ensuring that the manpower requirements align with the established workload and regulations set by the FAA.
8.
The practice that prevents and/or eliminates the possibility that one position will be studied under two or more Air Force manpower standard (AFMS) study effort is baseline
Correct Answer
C. Tagging
Explanation
Tagging is the practice that prevents and/or eliminates the possibility that one position will be studied under two or more Air Force manpower standard (AFMS) study efforts. By tagging a position, it is marked or labeled in a way that indicates it has already been studied or is currently being studied, ensuring that it is not included in multiple study efforts. This helps to maintain accuracy and avoid duplication of efforts in manpower standard studies.
9.
During initial baseline review, inconsistencies are forwarded to which agency for resolution prior to workload measurement?
Correct Answer
A. Headquarters Air Force/Manpower, Organization, and Resources Requirements Division
Explanation
During the initial baseline review, any inconsistencies are forwarded to the Headquarters Air Force/Manpower, Organization, and Resources Requirements Division for resolution before workload measurement.
10.
The first manpower requirements squadron (MRS) is set to begin an Air Force manpower standard (AFMS) study effort on civil engineering function. What document is used to define the study purpose, deliverables, scope, and application?
Correct Answer
C. Memorandum of agreement (MOA)
Explanation
A Memorandum of Agreement (MOA) is a document that is used to define the purpose, deliverables, scope, and application of a study effort. It is a formal agreement between two or more parties that outlines the terms and conditions of their collaboration. In this case, the first manpower requirements squadron (MRS) is conducting an Air Force manpower standard (AFMS) study on civil engineering function, and the MOA would be used to establish the parameters and objectives of the study. It would outline the responsibilities of each party involved and ensure that everyone is on the same page regarding the study's goals and outcomes.
11.
Which document is released across the Air Force and solicits manpower and functional points of contact for a managements engineering study effort?
Correct Answer
B. Study announcement message
Explanation
A study announcement message is released across the Air Force to solicit manpower and functional points of contact for a management engineering study effort. This document serves as a notification to inform relevant personnel about the study and request their involvement or assistance. It helps to coordinate and gather the necessary resources and support for the study. The study announcement message is an effective way to communicate the purpose and requirements of the study to the appropriate individuals within the Air Force.
12.
MSGT Tate is entering the familiarization phase of the Air Force manpower standard development process. Which comprehensive research method can he use to answer many initial question before conduction an onsite visit?
Correct Answer
D. Documenting review
Explanation
During the familiarization phase of the Air Force manpower standard development process, MSGT Tate can use the comprehensive research method of documenting review to answer many initial questions before conducting an onsite visit. Documenting review involves examining existing documents, reports, and data to gather information and gain insights. This method allows MSGT Tate to access a wealth of information without the need for physical presence or interviews. It helps in understanding the current practices, policies, and procedures, and provides a foundation for further analysis and decision-making.
13.
During the Documentation review of the familiarization phase of the Air Force manpower standard process, where do you check the defined workload drivers of the function under study?
Correct Answer
A. Manpower Standards
Explanation
During the Documentation review of the familiarization phase of the Air Force manpower standard process, you would check the defined workload drivers of the function under study in the Manpower Standards. This is because the Manpower Standards provide the guidelines and criteria for determining the appropriate staffing levels and workload drivers for different functions within the Air Force. By referring to the Manpower Standards, you can ensure that the workload drivers are accurately defined and accounted for in the manpower planning process.
14.
During documentation review in the familiarization phase of the Air Force manpower standard process, where do you look to uncover information regarding current and projected events concerning a function or work center under study?
Correct Answer
D. Organization of functional websites
Explanation
In order to uncover information regarding current and projected events concerning a function or work center under study during the documentation review in the familiarization phase of the Air Force manpower standard process, one should look at the organization of functional websites. These websites are likely to provide up-to-date information and announcements related to the function or work center being studied. They may include details about events, projects, and other relevant information that can help in understanding the current and future state of the function or work center.
15.
During documentation review in the familiarization phase of the Air Force manpower standard process, which documentation contains the career development courses of the function under study?
Correct Answer
C. Specialty training materials
Explanation
Specialty training materials contain the career development courses of the function under study during the documentation review in the familiarization phase of the Air Force manpower standard process. These materials are specifically designed to provide training and development opportunities for individuals in a particular specialty or field. They typically include information on the required courses, training objectives, and learning outcomes for individuals seeking to advance their career within that specific function.
16.
During the documentation review in the familiarization phase of the Air Force manpower standard development process, who validates assigned military and civilian strength information?
Correct Answer
B. Workcenter supervisor
Explanation
The workcenter supervisor is responsible for validating the assigned military and civilian strength information during the documentation review in the familiarization phase of the Air Force manpower standard development process. They have the authority and knowledge to ensure that the information is accurate and up to date.
17.
Encountering personnel that withhold valuable information is a disadvantage assciated with which method of obtaining information in the familiarization phase of the Air Force manpower standard process?
Correct Answer
D. Personal interviews
Explanation
Personal interviews can be a disadvantage in the familiarization phase of the Air Force manpower standard process because personnel may withhold valuable information. In a personal interview, individuals may be hesitant to share certain details or may intentionally withhold information that they deem sensitive or confidential. This can limit the effectiveness of the interview as a method of obtaining comprehensive and accurate information.
18.
When gathering information during the familiarization phase of the Air Force manpower standard development process, which skill level provides the best information about the processes and activities done inside the work center?
Correct Answer
B. 5
Explanation
Skill level 5 provides the best information about the processes and activities done inside the work center during the familiarization phase of the Air Force manpower standard development process. This is because skill level 5 represents the journeyman level, where individuals have a thorough understanding and experience in their field of work. They have acquired the necessary skills and knowledge to perform tasks independently and are familiar with the processes and activities within the work center. Therefore, skill level 5 would be able to provide the most accurate and detailed information during the familiarization phase.
19.
When conducting an onsite observation during the familiarization phase of the Air Force manpower standard development process, you must not
Correct Answer
A. Rely on general impressions for findings
Explanation
During the familiarization phase of the Air Force manpower standard development process, relying on general impressions for findings should be avoided. This is because general impressions may not provide accurate and detailed information about the work center's operations and requirements. Instead, it is important to conduct a thorough and in-depth observation by visiting a representative cross-section of the work center, dressing as the work center dresses, and avoiding prolonged observation to gather specific and reliable data for developing the manpower standards.
20.
During the study design phase of the Air Force manpower standard development process, who would you not allow, under any circumstance, to conduct the measurement needed to determine appropriate man-hours?
Correct Answer
C. Functional Community
Explanation
During the study design phase of the Air Force manpower standard development process, the Functional Community would not be allowed, under any circumstance, to conduct the measurement needed to determine appropriate man-hours. This is because the Functional Community represents the specific area or function within the Air Force and may have biased interests or perspectives that could compromise the objectivity and accuracy of the measurement. It is important to have an unbiased and independent party conduct the measurement to ensure the validity and fairness of the results.
21.
In the study design of the Air Force manpower standard development process, non-measurement approaches tend to be more expensive due to
Correct Answer
D. Less efficient requirement methodologies
Explanation
Non-measurement approaches in the Air Force manpower standard development process are more expensive because they use less efficient requirement methodologies. This means that these approaches may involve outdated or ineffective methods for gathering and analyzing data, which can result in wasted time and resources. By not utilizing more efficient requirement methodologies, the study design process becomes slower and less effective, leading to increased costs.
22.
One of the ways the workshop measurement is used in the study design phase of the Air Force manpower standard development process is to
Correct Answer
C. Develop a process oriented description (POD)
Explanation
The workshop measurement is used in the study design phase of the Air Force manpower standard development process to develop a process oriented description (POD). This means that the workshop measurement helps in creating a detailed and comprehensive description of the process involved in the standard development. This allows for a better understanding and documentation of the steps, tasks, and requirements involved in the process, which in turn helps in developing accurate and effective manpower standards.
23.
When preparing for a measurement workshop during the study design phase of the Air Force manpower standard development process, when selecting workshop participants, you must get a good mix of individuals from officer, enlisted, and civilian because
Correct Answer
B. Participants from each group bring a different set of values to the workshop
Explanation
When selecting workshop participants for a measurement workshop during the study design phase of the Air Force manpower standard development process, it is important to get a good mix of individuals from officer, enlisted, and civilian backgrounds because participants from each group bring a different set of values to the workshop. This diversity in values can lead to a more comprehensive and well-rounded discussion, allowing for a more accurate and unbiased end result.
24.
During the Study design phase of the Air Force manpower standard development process, participants' consensus, fewer scheduling issues, and less temporary duty travel are all benefits of
Correct Answer
B. Field measurement
Explanation
During the Study design phase of the Air Force manpower standard development process, field measurement is beneficial because it allows for participants' consensus to be reached more easily. This is because field measurement involves directly observing and collecting data on the tasks being performed, which provides a more accurate representation of the work being done. Additionally, field measurement reduces scheduling issues and the need for temporary duty travel, as data can be collected on-site without the need for participants to be physically present elsewhere.
25.
During the study design phase of the Air Force manpower standard development process, what is a drawback when using the field measurement approach?
Correct Answer
C. Data errors (corrections and adjustments) and variations in the data increase
Explanation
Using the field measurement approach during the study design phase of the Air Force manpower standard development process can have a drawback of data errors (corrections and adjustments) and variations in the data increasing. This means that there may be mistakes or inconsistencies in the collected data, which can affect the accuracy and reliability of the results. It is important to minimize these errors and variations to ensure the validity of the manpower standards being developed.
26.
When conducting field measurements during the study design phase of the Air Force manpower standard development process, which part of the measurement plan (MEASPLAN) outline contains a narrative description of conditions that affects the way work is performed at the input locations?
Correct Answer
C. Measurement instructions
Explanation
The measurement instructions in the MEASPLAN outline contain a narrative description of conditions that affect the way work is performed at the input locations. These instructions provide specific guidance on how to conduct the field measurements and what factors to consider when observing and recording data. They outline the procedures, techniques, and tools to be used, as well as any special considerations or conditions that may impact the measurements. By following the measurement instructions, researchers can ensure that the data collected accurately reflects the conditions and variables being studied.
27.
When developing potential workload factors during the study design phase of the Air Force manpower standard development process, which option is an example of a work unit?
Correct Answer
D. Number of tires changed
Explanation
The number of tires changed is an example of a work unit because it represents a specific task that can be measured and quantified. Work units are used to determine the workload requirements and resources needed for a particular job or task. In this case, the number of tires changed can be used to estimate the amount of work and manpower required for maintaining and servicing aircraft.
28.
When developing potential workload factors during the study design phase of the Air Force manpower standard development process, the work unit is not used when
Correct Answer
C. Building a correlation and regression model
Explanation
During the development of a correlation and regression model, the work unit is not used. Correlation and regression models are statistical techniques used to analyze the relationship between variables and to make predictions. In this context, the focus is on understanding how various factors are related to each other and how they influence the outcome variable. The work unit, which refers to the specific tasks or jobs performed within a unit, is not relevant in this statistical analysis. The correlation and regression model is built based on the variables of interest and their relationship, rather than on the specific work units involved.
29.
When, during the Air Force manpower standard development process, does potential workload factor identification begin?
Correct Answer
A. During study design and measurement activities
Explanation
During the study design and measurement activities, potential workload factor identification begins. This is because during this phase, the Air Force is conducting research and gathering data to understand the specific requirements and workload factors that need to be considered in the manpower standard. By identifying potential workload factors early on, the Air Force can ensure that they are accurately measuring and accounting for all relevant factors in the development of the manpower standard.
30.
During the study design phase of the Air Force manpower standard development process, what is the first step in the procedures for identifying potential workload factors for measurement?
Correct Answer
C. Identifying work units not controlled by the function under study
Explanation
In the study design phase of the Air Force manpower standard development process, the first step in identifying potential workload factors for measurement is to identify work units that are not controlled by the function under study. This step is important because it helps in understanding the scope of the study and ensures that all relevant work units are considered for measurement. By identifying work units that are not controlled by the function under study, the researchers can focus on the specific areas that they have control over and accurately measure the workload factors associated with those areas.
31.
Which option is an example of an Air Force-approved workload Factor? (WLF)
Correct Answer
C. Flying hours logged
Explanation
Flying hours logged is an example of an Air Force-approved workload factor (WLF) because it refers to the amount of time an aircraft spends in the air during a specific period. This is an important metric for the Air Force as it helps in tracking and managing the utilization of their aircraft fleet. By logging the flying hours, the Air Force can monitor the maintenance requirements, fuel consumption, and overall operational efficiency of their aircraft.
32.
What method is used to document processes and work activities for all production orientated work centers?
Correct Answer
D. Process flowcharts
Explanation
Process flowcharts are used to document processes and work activities for all production-oriented work centers. Flowcharts provide a visual representation of the steps involved in a process, allowing for easy understanding and communication of workflows. They help to identify bottlenecks, inefficiencies, and areas for improvement in the production process. By using symbols and arrows to represent each step and the flow of materials or information, process flowcharts provide a clear and concise documentation method for production-oriented work centers.
33.
When building a process oriented description, which phrase is an acceptable activity title for a process step?
Correct Answer
C. Repairs engine
Explanation
The phrase "Repairs engine" is an acceptable activity title for a process step because it accurately describes the action being performed, which is the repair of a single engine. The use of the present tense verb "repairs" indicates that the action is ongoing and emphasizes the specific task being carried out.
34.
If you write steps in a process oriented description in the plural form to cover as much work as possible, you may
Correct Answer
D. Increase the chance of error in the associated unit time values
Explanation
When writing steps in a process-oriented description in the plural form, it means that multiple tasks or actions are being described. This can lead to an increase in the chance of error in the associated unit time values. By including more steps, there is a higher likelihood of making mistakes or inaccurately estimating the time required for each task. Therefore, the more steps included, the greater the chance of error in the unit time values.
35.
During the measurement phase of the Air Force manpower standard process, which time classification category represents the basis for all other man-hours per month?
Correct Answer
A. Assigned
Explanation
During the measurement phase of the Air Force manpower standard process, the "Assigned" time classification category represents the basis for all other man-hours per month. This means that the number of hours assigned to a task or duty is used as a reference point for calculating the total man-hours required for that task or duty. The other time classification categories, such as "Available," "Productive," and "Nonavailable," are likely dependent on the initial assignment of hours and are measured in relation to the assigned time.
36.
When the lead team is classifying time, which classification does it consider for the work that is validated and is required by a major command or higher directives?
Correct Answer
A. Direct
Explanation
When the lead team is classifying time, they consider the "Direct" classification for the work that is validated and is required by a major command or higher directives. This means that the work directly contributes to the objectives and goals set by the major command or higher authorities.
37.
What measurement method is widely used and flexible work measurement method that can be used to set standards in practically any type of work center?
Correct Answer
C. Operational audit
Explanation
Operational audit is a widely used and flexible work measurement method that can be used to set standards in practically any type of work center. This method involves a comprehensive evaluation of an organization's operations, processes, and systems to identify areas of improvement and efficiency. It provides a holistic view of the work center's performance and helps in identifying opportunities for optimization. Unlike time study, work sampling, and simulation modeling, an operational audit focuses on assessing the overall effectiveness and efficiency of the work center rather than just measuring time or specific tasks.
38.
Which technique can you use to determine per accomplishment time when the measurement method employed is an operation audit?
Correct Answer
C. Technical estimate
Explanation
A technical estimate is a technique used to determine the time required to complete a specific task or accomplishment. It involves analyzing the technical aspects of the operation and making an estimate based on the available information. In the context of an operation audit, a technical estimate can be used to determine the time taken for each accomplishment by considering the technical requirements and constraints involved. This method helps in understanding the time required for each task and identifying any inefficiencies or bottlenecks in the operation.
39.
When using the good operator technique to determine per accomplishment time, you do not need pace rating if you have selected
Correct Answer
B. An average individual
Explanation
When using the good operator technique to determine per accomplishment time, the pace rating is not needed if you have selected an average individual. This is because the pace rating is used to compare the performance of an individual to the average performance, but when you have already selected an average individual, there is no need for this comparison. The average individual serves as the benchmark for determining per accomplishment time, and the pace rating becomes redundant in this case.
40.
During an operational audit, what method would you use to determine the per accomplishment time when it is affected by varying levels of complexity?
Correct Answer
D. Weighted average
Explanation
Weighted average would be the most appropriate method to determine the per accomplishment time when it is affected by varying levels of complexity during an operational audit. This method takes into account the differing levels of complexity and assigns weights accordingly to calculate an average. It provides a more accurate representation of the time required for each accomplishment, considering the impact of complexity on the overall time.
41.
During the operational audit, which method would you use to synthesized task man-hour values to determine the per accomplishment time?
Correct Answer
B. Standard data
Explanation
During an operational audit, the method of using standard data would be employed to synthesize task man-hour values and determine the per accomplishment time. Standard data refers to pre-determined time values for specific tasks, which have been established through past experience or industry benchmarks. By using standard data, an organization can estimate the time required to complete a task based on historical data or industry standards, allowing for more accurate planning and resource allocation.
42.
Which non-measurement method involves running developed models using differing constraints or conditions to determine the best mix of resource cost and level service obtained?
Correct Answer
C. Simulation modeling
Explanation
Simulation modeling involves running developed models using differing constraints or conditions to determine the best mix of resource cost and level of service obtained. This method allows for the testing and analysis of various scenarios, helping to optimize resource allocation and decision-making. By simulating real-world situations, organizations can evaluate the impact of different factors on cost and service levels, ultimately identifying the most effective strategies.
43.
Process simulation begins when you, the management engineer, identify the
Correct Answer
A. Work unit
Explanation
The correct answer is "work unit". In process simulation, the management engineer starts by identifying the work unit. The work unit refers to a specific task or activity that is being analyzed or simulated. It helps in determining the time, resources, and effort required to complete that particular task. By identifying the work unit, the management engineer can accurately simulate and analyze the process, making improvements and optimizations as necessary.
44.
Which organization is responsible for maintaining, modifying, documenting, distributing, and implementing the standard logistics composite model software application?
Correct Answer
C. The Air force Manpower Analysis Agency (AFMAA)
Explanation
The Air Force Manpower Analysis Agency (AFMAA) is responsible for maintaining, modifying, documenting, distributing, and implementing the standard logistics composite model software application.
45.
In simulation modeling, when considering queuing, how are cost such as morale defined?
Correct Answer
A. Intangible
Explanation
In simulation modeling, cost such as morale is defined as intangible. Intangible costs are those that cannot be easily quantified or measured in monetary terms. Morale is a subjective measure of the overall satisfaction, motivation, and well-being of individuals within a system. It is difficult to assign a specific dollar value to morale, as it is influenced by various factors such as work environment, relationships, and personal experiences. Therefore, it is considered an intangible cost in simulation modeling.
46.
When computing minimum manpower requirements, what do you calculate to provide enough time for workers to receive training that they cannot receive while performing their duties?
Correct Answer
D. Position qualification time
Explanation
Position qualification time is the correct answer because when computing minimum manpower requirements, it is important to calculate the time needed for workers to receive training that they cannot receive while performing their duties. This includes the time required for workers to gain the necessary qualifications and skills for their specific positions. By calculating the position qualification time, organizations can ensure that enough time is allocated for training and development, thus providing workers with the necessary skills to perform their duties effectively.
47.
When computing minimum manpower requirement, what do you calculate to account for work that individuals do before position coverage starts?
Correct Answer
A. Position related time
Explanation
When computing minimum manpower requirement, the calculation takes into account the position related time, which refers to the amount of time individuals spend on tasks related to their position before the coverage starts. This includes any preparatory work, planning, or coordination that needs to be done before the actual work begins. By considering the position related time, the calculation ensures that the manpower requirement adequately accounts for all the work that individuals need to do, even before they officially start covering the position.
48.
After a functional office or primary responsibility confirms minimum manpower requirements, you, the management engineer, show the manager how to meet the needed performance standards using
Correct Answer
B. Minimum standby time
Explanation
Minimum standby time refers to the amount of time that an employee is required to be available for work but is not actively engaged in productive tasks. In this context, the management engineer is showing the manager how to meet the needed performance standards by utilizing minimum standby time. This means that the engineer is suggesting that the manager schedule employees to be on standby during periods of low workload or when there is a possibility of increased demand. By doing so, the manager can ensure that the minimum manpower requirements are met while optimizing productivity and minimizing costs.
49.
What is a measurement method that recognizes the long-standing use of the manpower and standard procedures in a work center where some factor others than traditional workload dictates requirements?
Correct Answer
A. Whole manpower
Explanation
Whole manpower is a measurement method that recognizes the long-standing use of the manpower and standard procedures in a work center where some factor other than traditional workload dictates requirements. This means that the measurement takes into account the entire workforce and their roles and responsibilities, rather than just focusing on the workload. It acknowledges that there may be other factors, such as specific procedures or tasks, that require a certain level of manpower in the work center.
50.
Which whole manpower method captures a requirement that lacks any mathematical relationship to a workload driver and is not affected by varying workload volume?
Correct Answer
C. Constant manpower
Explanation
Constant manpower is the whole manpower method that captures a requirement that lacks any mathematical relationship to a workload driver and is not affected by varying workload volume. This means that regardless of the workload volume or any changes in workload drivers, the constant manpower method remains unchanged. It is a fixed number of manpower resources that are required to fulfill the requirement, regardless of any external factors.