Trade-off
Encyclopedia
A trade-off is a situation that involves losing one quality or aspect of something in return for gaining another quality or aspect. It implies a decision to be made with full comprehension of both the upside and downside of a particular choice.
, referring to the most preferred alternative given up. A trade-off, then, involves a sacrifice that must be made to obtain a certain product, rather than other products that can be made using the same required resources. For a person going to a basketball game, its opportunity cost is the money and time expended, say that would have been spent watching a particular television program.
. For example, in electrical engineering
, negative feedback
is used in amplifier
s to trade gain
for other desirable properties, such as improved bandwidth, stability
of the gain and/or bias point, noise
immunity, and reduction of nonlinear distortion
. The Golden Gate Bridge
is a prime rare example where few engineering
and aesthetic trade-offs had to be made.
In demography
, trade-off examples may include maturity, fecundity
, parental care, parity
, senescence
, and mate choice. For example, the higher the fecundity (# of offspring), the lower the parental care. Parental care as a function of fecundity would show a negative sloped linear graph.
In computer science
, trade-offs are viewed as a tool of the trade. A program can often run faster if it uses more memory (a space-time tradeoff
). Consider the following examples:
The Software Engineering Institute have a specific method for analysing tradeoffs, called the Architectural Tradeoff Analysis Method or ATAM.
Strategy board games almost always involve trade-offs. In chess
do you trade a bishop for position? In Go
, do you trade thickness for influence, and just when does the middle game begin?
The study of ethics
can be viewed as a system of competing interests that must be traded off against each other. (Is it ethical to use Nazi
science to prevent disease today?)
In medicine
, patients and physicians are often faced with difficult decisions involving trade-off. One example is localized prostate cancer
where patients need to weigh the possibility of a prolonged life expectancy against possible stressful treatment side-effects
(patient trade-off
).
Governmental trade-offs are among the most controversial political and social difficulties of any time. All of politics can be viewed as a series of trade-offs based upon which core values are most core to the most people or politicians.
In music
, the term "trade-off" can also refer to solo instruments that swap solo duties, such as musical groups with two lead guitar
ists, who both share guitar solos. The term is used frequently in heavy metal
, where bands often feature "twin guitars", such as Iron Maiden, Judas Priest
, Megadeth
, and Slayer
, all of which feature lead guitar song sections often involving 4 or more "trade-off" solos. A more limited number of bands, such as Dream Theater, also implement the trade-off with keyboards and lead guitar.
The NASA Systems Engineering Handbook (NASA 1995) suggests using multi-attribute utility
theoretic (MAUT) or the Analytic Hierarchy Process
(AHP). But, these too are not good with uncertainty, mixed information and teams. The authors suggest using probability based methods to maximize utility when uncertainty predominates, but give little detail on how to approach this.
In many situations, linear programming methods like the simplex algorithm
can be used but these too do not support uncertainty.
Another approach to supporting trade study information is to use the Bayesian Team Support (BTS) methods. These methods were designed to manage uncertain and evolving information. A paper describing this method isTrade Studies with Uncertain Information (Ullman 2006).
Examples from common life
In economics the term is expressed as opportunity costOpportunity cost
Opportunity cost is the cost of any activity measured in terms of the value of the best alternative that is not chosen . It is the sacrifice related to the second best choice available to someone, or group, who has picked among several mutually exclusive choices. The opportunity cost is also the...
, referring to the most preferred alternative given up. A trade-off, then, involves a sacrifice that must be made to obtain a certain product, rather than other products that can be made using the same required resources. For a person going to a basketball game, its opportunity cost is the money and time expended, say that would have been spent watching a particular television program.
Trade-offs in specific fields
Trade-offs are important in engineeringEngineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
. For example, in electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
, negative feedback
Negative feedback
Negative feedback occurs when the output of a system acts to oppose changes to the input of the system, with the result that the changes are attenuated. If the overall feedback of the system is negative, then the system will tend to be stable.- Overview :...
is used in amplifier
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
s to trade gain
Gain
In electronics, gain is a measure of the ability of a circuit to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale,...
for other desirable properties, such as improved bandwidth, stability
BIBO stability
In electrical engineering, specifically signal processing and control theory, BIBO stability is a form of stability for linear signals and systems that take inputs. BIBO stands for Bounded-Input Bounded-Output...
of the gain and/or bias point, noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
immunity, and reduction of nonlinear distortion
Distortion
A distortion is the alteration of the original shape of an object, image, sound, waveform or other form of information or representation. Distortion is usually unwanted, and often many methods are employed to minimize it in practice...
. The Golden Gate Bridge
Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco, on the northern tip of the San Francisco Peninsula, to...
is a prime rare example where few engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
and aesthetic trade-offs had to be made.
In demography
Demography
Demography is the statistical study of human population. It can be a very general science that can be applied to any kind of dynamic human population, that is, one that changes over time or space...
, trade-off examples may include maturity, fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
, parental care, parity
Parity (medicine)
In biology, parity is a technical term that refers to the number of times a female has given birth to a fetus.It can lead to some ambiguity for events occurring between 20 and 24 weeks, and for multiple pregnancies.-Enumeration:...
, senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...
, and mate choice. For example, the higher the fecundity (# of offspring), the lower the parental care. Parental care as a function of fecundity would show a negative sloped linear graph.
In computer science
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
, trade-offs are viewed as a tool of the trade. A program can often run faster if it uses more memory (a space-time tradeoff
Space-time tradeoff
In computer science, a space–time or time–memory tradeoff is a situation where the memory use can be reduced at the cost of slower program execution...
). Consider the following examples:
- By compressing an image, you can reduce transmission time/costs at the expense of CPU time to perform the compressionData compressionIn computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....
and decompression. - By using a lookup tableLookup tableIn computer science, a lookup table is a data structure, usually an array or associative array, often used to replace a runtime computation with a simpler array indexing operation. The savings in terms of processing time can be significant, since retrieving a value from memory is often faster than...
, you may be able to reduce CPUCentral processing unitThe central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
time at the expense of space to hold the table, e.g. to determine the parity of a byte you can either look at each bit individually (using shifts and masks), or use a 256-entry table giving the parity for each possible bit-pattern, or combine the upper and lower nibbles and use a 16-entry table. - For some situations (e.g. string manipulation), a compilerCompilerA compiler is a computer program that transforms source code written in a programming language into another computer language...
may be able to use inline code for greater speed, or call run-time routines for reduced memory; the user of the compiler should be able to indicate whether speed or space is more important.
The Software Engineering Institute have a specific method for analysing tradeoffs, called the Architectural Tradeoff Analysis Method or ATAM.
Strategy board games almost always involve trade-offs. In chess
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...
do you trade a bishop for position? In Go
Go (board game)
Go , is an ancient board game for two players that originated in China more than 2,000 years ago...
, do you trade thickness for influence, and just when does the middle game begin?
The study of ethics
Ethics
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...
can be viewed as a system of competing interests that must be traded off against each other. (Is it ethical to use Nazi
Nazism
Nazism, the common short form name of National Socialism was the ideology and practice of the Nazi Party and of Nazi Germany...
science to prevent disease today?)
In medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, patients and physicians are often faced with difficult decisions involving trade-off. One example is localized prostate cancer
Prostate cancer
Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...
where patients need to weigh the possibility of a prolonged life expectancy against possible stressful treatment side-effects
Adverse effect (medicine)
In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...
(patient trade-off
Patient trade-off
The trade-off dilemma refers to the choice between the expected beneficial and harmful effects in terms of patient survival and quality of life for a particular treatment. The choice involves a trade-off so it is of central importance for the patient and the physician to have access to empirical...
).
Governmental trade-offs are among the most controversial political and social difficulties of any time. All of politics can be viewed as a series of trade-offs based upon which core values are most core to the most people or politicians.
In music
Music
Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...
, the term "trade-off" can also refer to solo instruments that swap solo duties, such as musical groups with two lead guitar
Lead guitar
Lead guitar is a guitar part which plays melody lines, instrumental fill passages, guitar solos, and occasionally, some riffs within a song structure...
ists, who both share guitar solos. The term is used frequently in heavy metal
Heavy metal music
Heavy metal is a genre of rock music that developed in the late 1960s and early 1970s, largely in the Midlands of the United Kingdom and the United States...
, where bands often feature "twin guitars", such as Iron Maiden, Judas Priest
Judas Priest
Judas Priest are an English heavy metal band from Birmingham, England, formed in 1969. The current line-up consists of lead vocalist Rob Halford, guitarists Glenn Tipton and Richie Faulkner, bassist Ian Hill, and drummer Scott Travis. The band has gone through several drummers over the years,...
, Megadeth
Megadeth
Megadeth is an American heavy metal band from Los Angeles, California which was formed in 1983 by guitarist/vocalist Dave Mustaine, bassist Dave Ellefson and guitarist Greg Handevidt, following Mustaine's expulsion from Metallica. The band has since released 13 studio albums, three live albums, two...
, and Slayer
Slayer
Slayer is an American thrash metal band formed in Huntington Park, California, in 1981 by guitarists Jeff Hanneman and Kerry King. Slayer rose to fame with their 1986 release, Reign in Blood, and is credited as one of the "Big Four" thrash metal acts, along with Metallica, Megadeth and...
, all of which feature lead guitar song sections often involving 4 or more "trade-off" solos. A more limited number of bands, such as Dream Theater, also implement the trade-off with keyboards and lead guitar.
Analytical methods to support a trade study
Trade studies are essentially decision-making exercises. In the FAA Systems Handbook (FAA 2004), the decision analysis matrix (aka Pugh's method) is suggested to support the activities, but this method can not support uncertainty, a mix of quantitative and qualitative information, or teams. To manage uncertainty, the authors suggest supplementing point estimates of the outcome variables for each alternative with computed or estimated uncertainty ranges. The Standard Approach to Trade Studies (Felix 2004), an INCOSE paper from 2004 suggests a similar approach.The NASA Systems Engineering Handbook (NASA 1995) suggests using multi-attribute utility
Utility
In economics, utility is a measure of customer satisfaction, referring to the total satisfaction received by a consumer from consuming a good or service....
theoretic (MAUT) or the Analytic Hierarchy Process
Analytic Hierarchy Process
The Analytic Hierarchy Process is a structured technique for organizing and analyzing complex decisions. Based on mathematics and psychology, it was developed by Thomas L...
(AHP). But, these too are not good with uncertainty, mixed information and teams. The authors suggest using probability based methods to maximize utility when uncertainty predominates, but give little detail on how to approach this.
In many situations, linear programming methods like the simplex algorithm
Simplex algorithm
In mathematical optimization, Dantzig's simplex algorithm is a popular algorithm for linear programming. The journal Computing in Science and Engineering listed it as one of the top 10 algorithms of the twentieth century....
can be used but these too do not support uncertainty.
Another approach to supporting trade study information is to use the Bayesian Team Support (BTS) methods. These methods were designed to manage uncertain and evolving information. A paper describing this method isTrade Studies with Uncertain Information (Ullman 2006).