Where does schedule collide?

Marshall's 1890 Principles of Economics set out the demand schedule as a table that pairs each possible price of a good with the quantity buyers would purchase at that price, with a matching supply schedule doing the same for sellers. Reading down such a table shows how quantity falls as price rises, and plotting its rows gives the familiar demand curve. Later textbook treatments kept the table as the basic object and the curve as its picture. Here a schedule is a list of price-and-quantity pairs, not a plan of jobs run on machines over time or a rule that decides when a reward follows a response.[1]

Unit

One price-and-quantity pair, or the whole table across prices

Recovery means

Not applicable

Measured by

Estimated from market data by fitting quantity demanded against price

Skinner's 1938 The Behavior of Organisms showed that reinforcing only some responses, at fixed or irregular times, produces orderly and distinctive patterns of behaviour, and Ferster and Skinner's 1957 Schedules of Reinforcement mapped these arrangements in full. A schedule of reinforcement is the rule that states which responses, or which responses after how much elapsed time, are followed by a reinforcer, giving families such as fixed-ratio, variable-ratio, fixed-interval, and variable-interval. The rule, not any single reward, is what shapes the rate and timing of responding. Here a schedule is a contingency rule linking behaviour to its consequences, not a table of prices and quantities or an ordering of jobs across machines.[2][3]

Unit

One reinforcement rule, such as fixed-ratio 5 or variable-interval 30s

Recovery means

Not applicable

Measured by

Read from cumulative response records, whose slope shows the response rate under each rule

Johnson's 1954 paper Optimal two- and three-stage production schedules with setup times included gave an algorithm for ordering a set of jobs through machines so that the total time to finish them all is as short as possible. In this meaning a schedule is an assignment of tasks to resources and to positions in time: which job runs on which machine, and in what order, given that each machine handles one job at a time. The field it opened, scheduling theory, studies such orderings and the objectives, such as makespan, lateness, and flow time, that they try to optimise. Here a schedule is a worked-out plan of operations over time, not a price-and-quantity table or a rule governing when a reward is delivered.[4]

Unit

One complete assignment of jobs to machines and time positions

Recovery means

Not applicable

Measured by

Scored by an objective such as makespan, total flow time, or lateness