Get started

Glossary

Key terms and definitions for team coordination, shift work, and the gig economy.

A

Accessibility Volunteer management
Accessibility in volunteer management is the practice of designing programs, spaces, and tools so that all volunteers can participate fully, regardless of physical, sensory, or cognitive differences.
Accountability Volunteer management
Accountability in volunteer management is the shared responsibility of team members and coordinators to follow through on commitments, communicate honestly, and take ownership of outcomes.
Advancement opportunities Volunteer management
Advancement opportunities are structured pathways that allow volunteers to take on more responsibility, develop new skills, and grow within an organization over time.
Advocacy Volunteer management
Volunteer advocacy is the ongoing effort to communicate the value and impact of volunteers to an organization's leadership, funders, and broader community.
Agile workforce Shift work
An agile workforce is a labor pool structured around flexibility, where team members can shift between roles, tasks, or schedules quickly in response to changing demand.
Alignment Volunteer management
Alignment in volunteer management is the practice of ensuring that volunteer activities consistently support an organization's goals and mission.
Alternative work arrangements Gig economy
Alternative work arrangements are employment setups that fall outside traditional full-time, permanent employment, including part-time, contract, freelance, and on-demand work.
Ambassadors Volunteer management
Ambassadors, in volunteer management, are volunteers who represent an organization publicly and actively promote its mission and values to the wider community.
Ambiguity Volunteer management
Ambiguity in volunteer management is the uncertainty around roles, tasks, or expectations that makes it harder for volunteers to contribute effectively.
Annual report Volunteer management
An annual report in volunteer management is a document that summarizes a volunteer program's activities, achievements, and challenges over the course of a year.
Annualized hours roster Shift work
An annualized hours roster is a scheduling arrangement where an employee's total contracted working hours are distributed across a full year rather than divided into fixed weekly amounts.
Approval workflow Shift work
An approval workflow is a structured process in which managers review and either approve or decline shift requests, schedule changes, or shift trades before they take effect.
Assessment Volunteer management
Assessment in volunteer management is the ongoing process of evaluating volunteer performance and program effectiveness to understand impact, improve processes, and recognize contributions.
At-will employment Gig economy
At-will employment is a working arrangement where either the employer or the worker can end the relationship at any time, for any reason that isn't illegal, without notice or severance obligations.
Attraction Volunteer management
Volunteer attraction is the process organizations use to generate interest among potential volunteers and give them a compelling reason to get involved with a cause or team.
Attrition Shift work
Attrition is the gradual reduction of a workforce as employees leave through resignation, retirement, or termination and are not immediately replaced.
Auto-scheduling Shift work
Auto-scheduling is the automated generation of work schedules based on inputs like staff availability, role requirements, and labor rules, without building the roster by hand.
Availability Shift work
Availability is the set of times when a team member is able to work, used by managers to build schedules that match operational needs with individual circumstances.

C

Call-in shift Shift work
A call-in shift is a scheduling arrangement where an employee is placed on standby and must contact their employer shortly before the shift to confirm whether they are needed.
Call-out Shift work
A call-out is when an employee notifies their manager that they cannot work a scheduled shift, typically on short notice due to illness, a personal emergency, or another unexpected circumstance.
Career development Volunteer management
Career development in volunteer management refers to the process of volunteers gaining transferable skills and professional experience through meaningful roles within an organisation.
Casual workers Gig economy
Casual workers are people employed on an as-needed basis, with no guaranteed hours and no expectation of regular ongoing work.
Clopening Shift work
A clopening is a scheduling pattern where the same employee works a closing shift late at night and an opening shift the following morning, with only a few hours of rest between the two.
Cohesion Volunteer management
Cohesion, in volunteer management, is the sense of unity and shared purpose that holds a team together and makes collaborative work feel meaningful rather than transactional.
Collaboration Volunteer management
Collaboration in volunteer management is the practice of working toward shared goals with volunteers and partners, drawing on different skills and perspectives to produce better results.
Collaborative scheduling Shift work
Collaborative scheduling is a shift planning approach where team members have direct input into their own work schedules, rather than receiving assignments decided entirely by a manager.
Commitment Volunteer management
Commitment in volunteer management is the degree to which a volunteer reliably follows through on their role, showing up consistently, staying engaged, and completing their responsibilities over time.
Communication Volunteer management
Communication in volunteer management is the ongoing exchange of information between coordinators and volunteers that keeps everyone aligned, informed, and able to do their part.
Community engagement Volunteer management
Community engagement is the ongoing process of building two-way relationships between an organization and the people it serves, typically through coordinated volunteer and outreach efforts.
Compressed work week Shift work
A compressed work week is a scheduling arrangement where employees complete their full weekly hours across fewer than five days by working longer individual shifts.
Conflict management Volunteer management
Conflict management is the process of identifying, addressing, and resolving disagreements within a team in a way that preserves trust and keeps people working well together.
Continental shift pattern Shift work
A continental shift pattern is a rotating schedule where four teams share 24/7 coverage by cycling through day shifts, night shifts, and rest periods on a repeating four-week cycle.
Contingent worker Gig economy
A contingent worker is a person hired on a non-permanent basis, typically for a specific project, season, or defined period, rather than as an ongoing employee.
Contingent workforce Gig economy
A contingent workforce is a group of non-permanent workers, including freelancers, contractors, and temporary employees, engaged on a project or time-limited basis rather than through full-time employment.
Continuous improvement Volunteer management
Continuous improvement is the ongoing practice of regularly reviewing and refining volunteer programs so that each cycle performs better than the one before it.
Contract talent Gig economy
Contract talent refers to skilled professionals hired on a fixed-term or project basis rather than as permanent employees, typically to deliver a defined scope of work.
Contractor management Gig economy
Contractor management is the process of sourcing, coordinating, and overseeing independent contractors to ensure their work meets agreed standards and project goals.
Core hours Shift work
Core hours are the fixed time blocks during which all or most team members must be present, regardless of any flexible arrangements that apply outside those windows.
Coverage Shift work
Coverage is the state of having every scheduled shift staffed with the right number of people, with the right skills, at the right times to meet operational needs.
Credentialing Gig economy
Credentialing is the process of verifying a worker's qualifications, including their skills, work experience, education, licenses, and certifications, before they are hired or assigned to a role.
Crisis management Volunteer management
Crisis management in volunteer coordination is the practice of preparing for and responding to unexpected events that threaten the stability or continuity of a volunteer program.
Cross-training Shift work
Cross-training is the practice of teaching team members to perform more than one role so they can fill in across different positions when the schedule requires it.
Crowdsourcing Gig economy
Crowdsourcing is the practice of distributing tasks or collecting contributions from a large group of people, typically through an online platform, rather than a dedicated team or individual.
Cyclic roster Shift work
A cyclic roster is a repeating shift schedule where team members rotate through a fixed pattern of shifts over a set period, then restart the same cycle from the beginning.

D

Data management Volunteer management
Data management in volunteer coordination is the practice of organizing, maintaining, and securing volunteer records so that information stays accurate, accessible, and current.
Demand forecasting Shift work
Demand forecasting is the process of estimating how many staff members will be needed at a given time, based on historical workload patterns, expected activity, and other relevant factors.
Digital nomads Gig economy
Digital nomads are people who work remotely while moving between locations, using laptops and internet connectivity to do their jobs without being tied to a fixed office or city.
Direct and indirect agreements Gig economy
A direct agreement is a contract made directly between a worker and an employer, while an indirect agreement involves a third party, such as a staffing agency, sitting between the two.
Disaggregated work Gig economy
Disaggregated work is the practice of breaking a job or project into smaller, self-contained tasks that can be assigned and completed independently, typically by freelancers or gig workers.
Double shift Shift work
A double shift is when an employee works two consecutive shifts back-to-back, covering roughly double the standard shift length in a single stretch without a significant break in between.
DuPont schedule Shift work
The DuPont schedule is a 4-week rotating shift pattern using 12-hour shifts and four crews to deliver continuous 24/7 coverage, with a built-in block of 7 consecutive days off each cycle.

E

E-lancing Gig economy
E-lancing is the practice of finding, contracting, and delivering professional services entirely through digital platforms, without geographic limits or traditional employment structures.
Employee Experience (EX) Gig economy
Employee experience (EX) is the sum of all interactions a person has with an organization, from initial application through offboarding, covering recruitment, onboarding, day-to-day management, and recognition.
Employer Branding Gig economy
Employer branding is the reputation an organization builds as a place to work, shaped by the real experiences of its workers rather than by marketing or messaging alone.
Empowerment Volunteer management
Empowerment in volunteer management is the practice of giving volunteers the authority, trust, and resources to make decisions and take initiative within their roles, without needing approval at every step.
Engagement Volunteer management
Volunteer engagement is the process of involving volunteers in ways that connect to their interests, skills, and sense of purpose, so they stay motivated and committed over time.
Evaluation Volunteer management
Evaluation in volunteer management is the systematic process of assessing how well a volunteer program is performing and what outcomes it produces.
Expectation management Volunteer management
Expectation management is the practice of clearly communicating roles, responsibilities, and timelines so that every team member knows what they are accountable for and what they can expect from others.

F

Fatigue management Shift work
Fatigue management is the practice of designing work schedules and policies that limit tiredness accumulation in shift workers, protecting both their wellbeing and their ability to perform safely.
First-come, first-served Shift work
First-come, first-served is a shift assignment method where open shifts are available to all eligible team members simultaneously, and whoever claims a shift first gets it automatically.
Fixed roster Shift work
A fixed roster is a scheduling approach where team members work the same shifts on the same days every week, with no rotation or variation from one period to the next.
Fixed shifts Shift work
Fixed shifts are a work schedule where employees work the same set hours on the same days every week, with no rotation or variation.
Flex periods Shift work
A flex period is a defined time window within a work schedule during which team members can choose their own start or end time, rather than being assigned a fixed shift start.
Flexibility Volunteer management
Flexibility in volunteer management is the practice of adapting roles and schedules to fit volunteers' real availability and circumstances, rather than expecting everyone to conform to a fixed structure.
Flexible roster Shift work
A flexible roster is a scheduling approach where shift times or working hours vary based on availability and agreed boundaries, rather than following a fixed repeating pattern.
Flexible work arrangements Gig economy
Flexible work arrangements are employment structures that give workers control over when, where, or how they work, rather than requiring a fixed schedule, location, or set of tasks.
Flexible working Shift work
Flexible working is a work arrangement that allows people to vary when, where, or how long they work, outside of a fixed traditional schedule.
Flexitime Shift work
Flexitime is a scheduling arrangement that lets employees vary their start and end times around a fixed core window, while still completing their required total hours.
Float Shift work
A float is an employee who is cross-trained across multiple roles and deployed wherever staffing gaps arise, rather than being assigned to a fixed position.
Freelance management system (FMS) Gig economy
A freelance management system (FMS) is a software platform that helps businesses hire, contract, pay, and track freelance workers in a single workflow.
Freelancer Gig economy
A freelancer is a self-employed worker who offers skills and services to multiple clients on a project or contract basis, rather than working as a permanent employee for a single employer.
Full-time Equivalent (FTE) Gig economy
Full-time Equivalent (FTE) is a unit of measurement that converts hours worked by different people into a standardized full-time workload, allowing total workforce capacity to be expressed as a single comparable number.
Future of Work Gig economy
The future of work describes the ongoing shift in how work is organized, where it happens, and who does it, driven by automation, digital platforms, and changing worker and employer expectations.

O

On-call roster Shift work
An on-call roster is a schedule that identifies which team members are available to respond at short notice, ensuring coverage during emergencies, unexpected absences, or sudden increases in demand.
On-Demand Economy Gig economy
The on-demand economy is an economic model where consumers access goods and services immediately through digital platforms, and workers fulfill those requests on a flexible, as-needed basis.
On-Demand Hiring Gig economy
On-demand hiring is the practice of bringing in workers only when a specific need arises, rather than maintaining a fixed headcount in advance.
Onboarding Volunteer management
Onboarding in volunteer management is the process of introducing new volunteers to an organization, its mission, and their specific roles to help them feel prepared and connected from the start.
Open shifts Shift work
Open shifts are unassigned work periods posted by a manager that any eligible team member can claim, rather than being pre-allocated to a specific person in advance.
Opportunities Volunteer management
Opportunities in volunteer management are the specific roles, tasks, or activities that an organization makes available for volunteers to sign up for, each with a defined scope and clear expectations.
Orientation Volunteer management
Volunteer orientation is a structured onboarding process that introduces new volunteers to an organization's mission, policies, expectations, and workflows before they begin their first shift.
Outcomes Volunteer management
Outcomes are the real-world changes that result from volunteer activities, such as improvements in community wellbeing, skill development, or measurable progress toward an organization's mission.
Outreach Volunteer management
Volunteer outreach is the process of proactively connecting with potential volunteers and communities to invite them into your organization's work and cause.
Overstaffing Shift work
Overstaffing is a scheduling situation where more people are assigned to a shift than the workload actually requires, resulting in underutilized labor and unnecessary cost.
Overtime Shift work
Overtime is time worked beyond an employee's standard scheduled hours, typically compensated at a higher rate, often 1.5 times the regular hourly wage.

P

Panama schedule Shift work
The Panama schedule is a 14-day rotating shift pattern using a 2-2-3 cycle across four crews to deliver continuous 24/7 coverage with 12-hour shifts.
Part-time roster Shift work
A part-time roster is a schedule that assigns shifts to team members working fewer hours than full-time staff, typically under 30 to 40 hours per week.
Pay equity Gig economy
Pay equity is the practice of compensating workers equally for work that is equal or comparable in value, regardless of gender, race, age, or other personal characteristics.
Payroll integration Shift work
Payroll integration is the process of connecting a scheduling or time-tracking system to a payroll platform so that hours worked and shift data transfer automatically, without manual re-entry.
Peak hours Shift work
Peak hours are the recurring time windows during a workday or week when customer demand is highest and staffing needs are greatest.
Performance Review Volunteer management
A volunteer performance review is a structured, recurring evaluation of a volunteer's contributions, used to recognize achievements, give feedback, and align individual goals with the organization's mission.
Pick-up shifts Shift work
Pick-up shifts are unassigned shifts posted outside the regular schedule that team members can claim voluntarily, typically to cover absences or unexpected gaps in staffing.
Pitman schedule Shift work
A Pitman schedule is a 14-day shift rotation based on a 2-2-3 cycle, where team members work 7 shifts per fortnight with a built-in three-day break every other week.
Policies Volunteer management
A volunteer policy is a formal guideline that defines expected behaviors, procedures, and standards for volunteers within an organization.
Preference-based scheduling Shift work
Preference-based scheduling is a shift assignment approach that incorporates team members' stated availability and working hour preferences into the roster-building process, alongside operational coverage requirements.

R

Recognition Volunteer management
Recognition in volunteer management is the practice of acknowledging individual volunteers for their contributions in ways that feel genuine and specific to the person.
Recruitment Volunteer management
Recruitment in volunteer management is the process of identifying, attracting, and selecting people to join an organization as volunteers.
Referral Program Volunteer management
A referral program is a structured approach to volunteer recruitment where existing volunteers are encouraged to invite people from their own networks to join the organization.
Relief roster Shift work
A relief roster is a list of team members who are available to cover shifts when colleagues are absent due to illness, vacation, or other unplanned leave.
Retainer contract Gig economy
A retainer contract is an agreement where a client pays a freelancer a fixed recurring fee in exchange for guaranteed availability over a set period.
Retention Volunteer management
Volunteer retention is the ongoing effort by an organization to keep volunteers engaged, motivated, and returning over time rather than drifting away after a single experience.
Roster Shift work
A roster is a schedule that shows which team members are assigned to which shifts, including the dates, times, and roles involved.
Rotating roster Shift work
A rotating roster is a scheduling system where team members cycle through different shifts in a repeating pattern, rather than being permanently assigned to the same hours each week.

S

Schedule adherence Shift work
Schedule adherence is a measure of how closely team members follow their assigned work schedules, tracked by on-time arrival, full shift completion, and absence of unplanned no-shows.
Schedule lock Shift work
A schedule lock is a defined cutoff point after which a shift schedule is treated as final, and any changes require manager approval before taking effect.
Schedule optimization Shift work
Schedule optimization is the process of building work schedules that align staffing levels with actual demand, taking into account team availability, skills, and shift preferences.
Schedule request period Shift work
A schedule request period is a defined window of time before a new schedule is published, during which team members can submit their availability, preferences, or time-off requests.
Schedule template Shift work
A schedule template is a pre-built shift structure that managers can reuse across scheduling periods, capturing the recurring roles, time slots, and coverage patterns a team regularly needs.
Schedule transparency Shift work
Schedule transparency is the practice of making work schedules visible to all team members, so everyone can see who is working which shifts, when, and how assignments are distributed.
Scheduling Volunteer management
Scheduling is the process of assigning people to specific time slots or tasks to ensure the right coverage is in place when and where it is needed.
Scheduling conflicts Shift work
A scheduling conflict is a situation where an assigned shift overlaps with another commitment, violates a work rule, or falls outside a team member's stated availability, making the schedule unworkable without a change.
Scheduling constraints Shift work
Scheduling constraints are the rules, limitations, and requirements from labor law, individual availability, and operational needs that determine whether a work schedule is valid before it's published.
Scheduling fairness Shift work
Scheduling fairness is the practice of distributing desirable and undesirable shifts equitably across a team, so no single person consistently works the least convenient hours while others always get the preferred ones.
Scheduling horizon Shift work
A scheduling horizon is the period of time in advance for which work schedules are planned and published, defining how far ahead managers create and share shifts with their team.
Seasonal roster Shift work
A seasonal roster is a work schedule that adjusts staffing levels to match predictable fluctuations in demand across different times of the year.
Seasonal workers Shift work
Seasonal workers are employees hired for a fixed, recurring period to cover predictable surges in demand tied to a specific time of year, such as a harvest season, holiday period, or tourist peak.
Self-employed worker Gig economy
A self-employed worker is someone who works for themselves rather than for an employer, taking on clients or projects independently and bearing full responsibility for their own income, taxes, and expenses.
Self-scheduling Shift work
Self-scheduling is a shift planning approach where team members choose their own shifts from available options, within parameters set by management.
Self-scheduling rules Shift work
Self-scheduling rules are the parameters that define how team members can claim or sign up for shifts on their own, within boundaries set by whoever manages the schedule.
Shift bidding Shift work
Shift bidding is a scheduling process where team members submit preferences for shifts they want to work, and managers assign those shifts based on agreed criteria such as seniority, availability, or sign-up order.
Shift differential Shift work
Shift differential is additional pay that team members receive for working less desirable shifts, such as nights, weekends, or holidays, expressed as a percentage of base pay or a flat hourly addition.
Shift eligibility Shift work
Shift eligibility refers to the criteria that determine which team members can sign up for or be assigned to a specific shift, based on qualifications, role, or other defined requirements.
Shift Fatigue Shift work
Shift fatigue is the cumulative physical and mental exhaustion that develops when people work irregular or rotating shift patterns over an extended period, disrupting sleep and recovery.
Shift marketplace Shift work
A shift marketplace is a scheduling system where open shifts are posted in a shared space and team members can browse and claim them based on their own availability.
Shift pattern Shift work
A shift pattern is a recurring schedule structure that defines when team members work and when they rest, repeated over a fixed cycle of days or weeks.
Shift release Shift work
Shift release is the process by which a scheduled team member makes their assigned shift available for others to claim, typically through a shared pool visible to the whole team.
Shift rotation Shift work
Shift rotation is a scheduling practice where team members cycle through different shifts on a recurring basis, distributing morning, afternoon, and overnight hours across the group over time rather than assigning them permanently.
Shift swapping Shift work
Shift swapping is the practice of two team members exchanging their scheduled shifts so that both shifts remain covered while each person's availability is accommodated.
Shift trade Shift work
A shift trade is an arrangement where two team members swap their assigned shifts, so each works the other's original slot instead of their own.
Shift workers Shift work
Shift workers are employees who work scheduled time blocks outside standard business hours, including evenings, nights, and weekends, to keep operations running continuously.
Short-term assignments Gig economy
A short-term assignment is a work engagement with a defined end date, typically lasting from a few days to a few months, scoped around a specific task or temporary business need rather than ongoing employment.
Short-term contracts Gig economy
A short-term contract is a legally binding employment agreement for a defined, limited period, with a fixed end date agreed upon by both parties from the start.
Side hustle Gig economy
A side hustle is a secondary source of income pursued alongside a main job, on a self-directed basis with no fixed schedule imposed by an employer.
Skill-sharing platforms Gig economy
Skill-sharing platforms are online marketplaces where individuals offer expertise, services, or knowledge to clients or learners, typically in exchange for payment or reciprocal skills.
Split roster Shift work
A split roster is a scheduling approach where part of the team works a fixed, repeating schedule while another part rotates across different shifts or days on a defined cycle.
Split shift Shift work
A split shift is a work schedule where an employee's day is divided into two or more separate working periods, with an extended unpaid break of several hours in between.
Spot bonus Gig economy
A spot bonus is a one-time financial reward given to a team member immediately after a specific contribution, outside of any scheduled pay cycle or formal review process.
Staggered shift roster Shift work
A staggered shift roster is a scheduling approach where team members are assigned different start and end times across the day, creating overlapping coverage rather than a single uniform shift block.
Sustainability Volunteer management
Sustainability in volunteer management is the ability of a program to maintain consistent participation, impact, and resources over time without burning out its people or exhausting its funding.
Swing shift Shift work
A swing shift is a work schedule that runs between the day shift and the night shift, typically covering late afternoon through late evening, such as 3 PM to 11 PM.

T

Talent Acquisition Technology Gig economy
Talent acquisition technology is the category of software tools organizations use to find, attract, screen, and hire candidates, from job posting and applicant tracking to AI-assisted resume screening.
Talent marketplace Gig economy
A talent marketplace is a platform where employers and workers connect directly to fill roles, shifts, or project-based work, either within a single organization or open to a broader pool of contractors and freelancers.
Talent pool Gig economy
A talent pool is a curated database of pre-vetted candidates or workers that an organization maintains so it can fill roles quickly without starting recruitment from scratch each time.
Telecommuting Shift work
Telecommuting is a work arrangement where employees perform their job duties from a location outside a traditional office, typically from home, using digital tools to communicate and collaborate with their team.
Temporary Staffing Shift work
Temporary staffing is the practice of hiring workers for a defined, limited period to fill a short-term need, such as seasonal demand, a specific project, or cover for absent permanent staff.
Temporary to Permanent Conversion Gig economy
Temporary to permanent conversion is the process of transitioning a worker from a fixed-term or contingent role into an ongoing, permanent position within the same organization.
Temporary worker Shift work
A temporary worker is a person hired for a defined period to fill a specific role, rather than being taken on as a permanent member of a team.
Time clock Shift work
A time clock is a system that records when team members start and end their shifts, creating a timestamped log of actual hours worked.
Training Volunteer management
Volunteer training is the process of equipping people with the knowledge, skills, and context they need to carry out their roles effectively within an organization.
Transparency Volunteer management
Transparency in volunteer management is the practice of openly sharing information, decisions, and processes with volunteers so they understand what is happening and why.
Trust Volunteer management
Trust in volunteer management is the confidence volunteers have that an organization will follow through on its commitments, treat them fairly, and value their contributions.

V

Variable workforce Shift work
A variable workforce is a staffing model that combines a permanent core team with flexible workers, such as part-time staff, temporary hires, and freelancers, to scale labor up or down based on demand.
Vendor Management System (VMS) Gig economy
A Vendor Management System (VMS) is a software platform organizations use to manage relationships with external staffing agencies, contractors, and contingent labor suppliers from one centralized place.
Volunteer agreement Volunteer management
A volunteer agreement is a formal document that defines the responsibilities, expectations, and commitments between an organization and its volunteers.
Volunteer database Volunteer management
A volunteer database is a centralized system for storing and managing volunteer information, including contact details, availability, skills, and participation history.
Volunteer experience Volunteer management
Volunteer experience is the overall quality of what volunteers encounter with an organization, including how they are welcomed, supported, communicated with, and recognized throughout their involvement.
Volunteer lifecycle Volunteer management
The volunteer lifecycle is the sequence of stages a volunteer moves through within an organization, from initial recruitment through onboarding, active engagement, and eventual exit.
Volunteer Management System Volunteer management
A volunteer management system (VMS) is software that helps organizations recruit, coordinate, track, and communicate with volunteers from a single platform.
Volunteer Recognition Events Volunteer management
Volunteer recognition events are organized gatherings where organizations celebrate and acknowledge volunteer contributions, typically through ceremonies, shared meals, or informal get-togethers.
Volunteer roles Volunteer management
Volunteer roles are defined sets of responsibilities assigned to individuals within an organization, describing what tasks they are expected to perform and how their contribution supports the overall mission.
Volunteer satisfaction Volunteer management
Volunteer satisfaction is a measure of how fulfilled, valued, and engaged volunteers feel in their roles within an organization over time.