Explore science by method, field &amp; evidence.

Aggregate Planning

Aggregate Planning (or Sales & Operations Planning, S&OP) is a collaborative, iterative process that balances demand and supply at a high level—typically grouping products into families and planning over a 3–18 month horizon. Developed formally by Tom Wallace and popularized through APICS, aggregate planning helps orga

2 sources1992

Analytic Hierarchy Process for Strategic Priorities

The Analytic Hierarchy Process (AHP) applied to strategic priorities is a multi-criteria decision method that structures a complex strategy choice into a hierarchy of goal, criteria, and alternatives, then derives priority weights from expert pairwise comparisons. Thomas Saaty developed AHP in the 1970s and set out its

2 sources1980

Assembly Line Balancing

Assembly Line Balancing is the problem of distributing a sequence of assembly tasks across a series of workstations on a production line such that work is evenly distributed, idle time is minimized, and throughput constraints are satisfied. The goal is to assign tasks to stations such that the total work time at each s

2 sources2010

Bullwhip Effect

The Bullwhip Effect is a phenomenon in supply chain management where small fluctuations in end-customer demand cause progressively larger fluctuations in orders as one moves upstream from retail to distributors to manufacturers to suppliers. First formally documented by Jay Forrester in his 1961 system dynamics work, a

2 sources1961

Closed-Loop Supply Chain

A closed-loop supply chain (CLSC) integrates forward logistics (moving products to customers) with reverse logistics (recovering products, components, or materials from customers) to optimize resource recovery, reduce waste, and minimize environmental impact. Products flow forward for customer use, then flow backward f

2 sources2003

marketing management

Consumer Involvement Scale

The Consumer Involvement Scale (CIS), developed by Zaichkowsky (1985), measures the degree to which a consumer feels personally invested in a product, brand, or purchase decision. Originally a 20-item instrument operationalizing the concept of 'personal relevance,' the CIS was refined to 10 items in 1994 (Revised Perso

2 sources1985

Cross-Docking

Cross-docking is a logistics strategy in which products arriving at a distribution center from suppliers are unloaded, sorted, consolidated, and immediately reloaded onto outbound vehicles destined for customers, with minimal or no storage time. Rather than storing inventory in a warehouse, products flow through in 24–

2 sources2007

Data Envelopment Analysis (Productivity)

Data envelopment analysis (DEA) is a nonparametric, linear-programming technique for measuring the relative productive efficiency of comparable units — firms, plants, hospitals, schools, bank branches — that convert multiple inputs into multiple outputs. Introduced by Charnes, Cooper, and Rhodes in 1978 and rooted in F

2 sources1978

Data Envelopment Analysis of Firm Strategic Efficiency

Data Envelopment Analysis (DEA) of firm strategic efficiency benchmarks each firm or strategic business unit against a best-practice frontier built directly from the data, with no need to assume prices, weights, or a functional form. Introduced by Charnes, Cooper and Rhodes in 1978 under constant returns to scale (the

2 sources1978

healthcare management

DEA Hospital Efficiency

Data Envelopment Analysis (DEA) is a linear programming technique for measuring the relative efficiency of multiple hospitals using multiple inputs and outputs. Introduced by Charnes, Cooper, and Rhodes in 1978, DEA has become the standard method for benchmarking hospital performance in healthcare systems worldwide.

3 sources1978

tourism recreation

Destination Competitiveness Index

The Destination Competitiveness Index operationalizes the Ritchie-Crouch model, the most influential conceptual framework for understanding why some tourism destinations outperform others. Crouch and Ritchie argued in 1999, and elaborated in their 2003 book The Competitive Destination, that a destination's ability to a

2 sources2003

organizational behavior

Emotional Exhaustion Scale

The Emotional Exhaustion subscale is one of three core dimensions of the Maslach Burnout Inventory (MBI), developed by Maslach and Jackson in 1981. Emotional exhaustion represents the first stage of burnout, characterized by feeling emotionally drained, fatigued, and depleted as a result of work. The nine-item subscale

2 sources1981

Environmentally Extended Input-Output Analysis

Environmentally extended input-output (EEIO) analysis appends satellite accounts of physical environmental flows — greenhouse-gas emissions, energy, water, land, and materials — to a monetary input-output table so that environmental burdens can be allocated through supply chains to the final demand that ultimately driv

2 sources1970

Facility Layout (SLP)

Systematic Layout Planning (SLP) is a structured methodology developed by Richard Muther in the 1960s–1970s for designing optimal plant and facility layouts. The approach systematizes the consideration of material flow, personnel movement, equipment relationships, and space constraints to minimize material handling cos

2 sources1973

Ghosh Supply-Driven Model

The Ghosh model is the supply-side counterpart to the Leontief demand-driven input-output system, introduced by Ambica Ghosh in 1958. Rather than fixing the recipe of inputs per unit of output, it fixes allocation coefficients — the share of each sector's output sold to every downstream buyer — and asks how a change in

2 sources1958

tourism

Hotel DEA Efficiency Analysis

Hotel DEA efficiency analysis applies data envelopment analysis, the linear-programming frontier method introduced by Charnes, Cooper, and Rhodes in 1978, to benchmark how efficiently hotels convert their inputs into outputs. Rather than assuming a functional form, DEA builds a best-practice frontier directly from the

2 sources1978

tourism

Hotel Revenue Management

Hotel revenue management, also called yield management, is the decision discipline of selling the right room to the right guest at the right price at the right time to maximize revenue from a fixed, perishable inventory. Sheryl Kimes's 1989 paper crystallized the concept for capacity-constrained service firms, identify

2 sources1989

Input-Output Analysis

Input-output analysis is a quantitative framework for representing the interdependence between the industries of an economy, introduced by Wassily Leontief in 1936. It records the flows of goods and services between sectors in a transactions table, derives fixed technical coefficients describing how much each industry

2 sources1936

Input-Output Life Cycle Assessment

Input-output life cycle assessment (IO-LCA) estimates the environmental burdens of a product or service over its life cycle by representing it as a unit of final demand within an environmentally extended input-output model. Rather than mapping individual processes, it leverages the Leontief inverse to capture the compl

2 sources2006

Input-Output Multiplier Analysis

Input-output multiplier analysis converts the Leontief inverse into summary impact coefficients that answer how much total output, household income, or employment an economy generates per unit of final demand directed at a given sector. Building directly on Leontief's inter-industry accounting, it distinguishes the ini

2 sources1936

Inventory Routing

The Inventory Routing Problem (IRP) is an optimization problem that jointly determines inventory levels at customer locations, delivery routes, and shipment quantities to minimize total logistics and inventory holding costs. Rather than treating inventory management and vehicle routing as separate decisions, IRP recogn

2 sources2014

Job Shop Scheduling

Job shop scheduling is the problem of assigning a set of jobs (tasks) to a set of machines (resources) over time, subject to precedence and capacity constraints, with the goal of optimizing performance metrics such as makespan (total completion time), lateness, or cost. The job shop problem is a classic combinatorial o

2 sources2016

Kanban

Kanban is a pull-based production control system developed by Taiichi Ohno at Toyota in the 1950s that uses visual signals (traditionally cards or bins) to trigger production and movement of materials based on actual demand rather than forecasts. The Japanese word 'kanban' means 'visual card' or 'sign,' and the system

2 sources1950

Leontief Price Model

The Leontief price model is the cost-side dual of the quantity input-output system: instead of asking how much each sector must produce to meet final demand, it asks what unit price each sector must charge to cover its intermediate-input costs plus its primary-input (value-added) payments. Solving the dual equation p'

2 sources1936

Malmquist Firm Productivity Index

The Malmquist firm productivity index measures how a firm's total factor productivity changes between two periods and decomposes that change into two strategically meaningful parts: catching up to best practice (efficiency change) and the best-practice frontier itself shifting (technical change). The index is grounded

2 sources1994

Material Requirements Planning

Material Requirements Planning (MRP) is a computerized system developed by Joseph Orlicky in the 1970s that calculates material requirements based on master production schedules and bill-of-materials data. MRP determines what materials to buy, how much to order, and when to order them to meet production demand while mi

2 sources1975

Overall Equipment Effectiveness

Overall Equipment Effectiveness (OEE) is a composite key performance indicator that quantifies how effectively a manufacturing operation uses its equipment relative to its full potential. Developed by Seiichi Nakajima in 1988 as a cornerstone metric of Total Productive Maintenance (TPM), OEE multiplies three loss facto

1 source1988

healthcare management

Queuing Theory in Healthcare

Queuing theory is a mathematical discipline that models waiting lines, service capacity, and customer (patient) flow. Developed initially by Agner Erlang for telecommunications in 1909, it has been extensively applied to healthcare to analyze and optimize emergency departments, outpatient clinics, surgical suites, and

3 sources1909

Real Options Strategy Valuation

Real options strategy valuation treats discretionary strategic investments - the chance to defer, expand, contract, stage, switch, or abandon a project - as financial-style options whose value comes from managerial flexibility under uncertainty. Dixit and Pindyck's 1994 Investment under Uncertainty established the theo

3 sources1994

Real Options Valuation

Real options valuation applies the theory of financial options to real (physical, strategic) investment decisions, valuing the managerial flexibility to defer, expand, contract, switch, or abandon a project as uncertainty resolves over time. Where standard discounted-cash-flow analysis assumes a now-or-never commitment

2 sources1994

Reliability Block Diagram

A Reliability Block Diagram (RBD) is a visual representation of a system's architecture that models how component reliabilities combine to determine overall system reliability. Each block represents a component or subsystem with a known reliability (probability of functioning without failure), and connections between b

2 sources2010

Root Cause Analysis

Root Cause Analysis (RCA) is a structured, systematic method for identifying the fundamental causes of defects, failures, or undesirable outcomes rather than treating surface-level symptoms. Popularised by Japanese quality engineer Kaoru Ishikawa in the 1960s–1980s, and formally codified in his 1986 Guide to Quality Co

1 source1986

SCOR Model

The Supply Chain Operations Reference Model is a standardized framework for supply chain management developed by the Supply Chain Council (now APICS) in 1996. SCOR provides a structured approach to identify, evaluate, and improve supply chain processes across organizations, regardless of industry. It integrates plannin

2 sources1996

Six Sigma DMAIC

Six Sigma DMAIC is a data-driven, five-phase process improvement methodology — Define, Measure, Analyze, Improve, and Control — used to reduce defects and process variation to fewer than 3.4 defects per million opportunities. Originating at Motorola in the 1980s and systematized by practitioners including Pyzdek and Ke

1 source2014

healthcare management

Six Sigma in Healthcare

Six Sigma is a data-driven quality improvement methodology originating at Motorola in 1986 that aims to reduce process variation and defects to achieve near-perfect quality (3.4 defects per million opportunities). In healthcare, Six Sigma uses statistical analysis and structured project methodology (DMAIC: Define-Measu

3 sources1986

SMED

Single Minute Exchange of Die (SMED) is a systematic approach developed by Shigeo Shingo in the 1980s to drastically reduce the time required to changeover equipment from producing one product to another. The methodology, part of the Toyota Production System, aims to reduce setup time to a single-digit minute range (id

2 sources1985

Social Accounting Matrix

A social accounting matrix (SAM) is a square, double-entry table that records all transactions among the production sectors, factors of production, institutions (households, firms, government), and the rest of the world in an economy for a given year. It extends the input-output table by closing the circular flow of in

2 sources1962

Social Cost-Benefit Analysis

Social cost-benefit analysis (SCBA) appraises public investment projects from the standpoint of society as a whole rather than a private investor. It values inputs and outputs at shadow prices that reflect their true opportunity cost to the economy — correcting market prices for taxes, subsidies, trade distortions, and

2 sources1974

Stochastic Frontier Firm Efficiency Analysis

Stochastic frontier analysis (SFA) estimates how far a firm falls short of the best attainable output for its inputs while explicitly separating that shortfall from random noise. Aigner, Lovell and Schmidt's 1977 model introduced the defining idea: a production frontier whose error term is the sum of a symmetric, two-s

2 sources1977

Structural Decomposition Analysis

Structural decomposition analysis (SDA) explains how an input-output quantity — total output, value added, energy use, or emissions — changed between two periods by attributing the change to its underlying structural determinants, chiefly shifts in production technology (the Leontief inverse) versus shifts in the level

2 sources1998

Supply Chain Integration Scale

Supply Chain Integration (SCI) refers to an organization's capacity to seamlessly coordinate and align processes, information, and incentives across internal functions and with external suppliers and customers. Flynn et al. (2010) operationalized SCI into three complementary dimensions in the Journal of Operations Mana

3 sources2010

SWOT-AHP Hybrid Analysis

SWOT-AHP, also called A'WOT, is a hybrid strategy method that quantifies an ordinary SWOT analysis by applying the Analytic Hierarchy Process to its factors. Kurttila, Pesonen, Kangas, and Kajanus introduced the technique in 2000, motivated by the fact that classic SWOT lists strengths, weaknesses, opportunities, and t

2 sources2000

Theory of Constraints

The Theory of Constraints (TOC) is a management philosophy and continuous improvement framework introduced by Eliyahu Goldratt in his 1984 novel The Goal and formalized in his 1990 book. TOC holds that every system has at least one constraint — a bottleneck that limits the system's overall throughput — and that systema

1 source1990

Total Productive Maintenance

Total Productive Maintenance (TPM) is a comprehensive maintenance management approach developed by Seiichi Nakajima in the late 1980s that emphasizes employee involvement, preventive maintenance, and continuous improvement to maximize equipment effectiveness. Unlike traditional reactive maintenance, TPM integrates main

2 sources1988

tourism economics

Tourism Input-Output Analysis

Tourism input-output analysis applies Wassily Leontief's inter-industry framework to measure how tourist spending reverberates through an entire economy. An input-output table records, sector by sector, how much each industry buys from every other industry to produce its output. By treating tourism expenditure as a fin

2 sources1989

tourism economics

Tourism Multiplier Analysis

Tourism multiplier analysis quantifies how much total economic activity a destination gains from each unit of tourist spending, once that spending circulates through the local economy. When a visitor pays for a hotel room, the money does not stop there: the hotel pays wages, buys food and laundry services, and its supp

2 sources1982

tourism economics

Tourism Satellite Account

A Tourism Satellite Account (TSA) is the internationally agreed statistical framework for measuring the economic contribution of tourism in a way that is consistent with, and comparable to, the System of National Accounts. Because tourism is not a single industry but a demand-defined activity that cuts across accommoda

2 sources2008

marketing science

TURF Analysis

TURF analysis — Total Unduplicated Reach and Frequency — answers a portfolio question: which limited set of products, flavors, features, or messages reaches the largest number of distinct customers with at least one option they like? The reach-and-frequency idea originated in media planning, where reach is the share of

2 sources2013

Value Stream Mapping

Value Stream Mapping (VSM) is a lean management technique used to visualize, analyze, and improve the flow of materials and information required to bring a product or service from raw input to customer delivery. Introduced by Mike Rother and John Shook in their 1999 workbook Learning to See, VSM draws on the Toyota Pro

1 source1999