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rough order of magnitude
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См. также в других словарях:
rough order of magnitude — n. Fancy way of saying to make a wild [ass] guess … Business English jargon and slang
Orders of magnitude (numbers) — The logarithmic scale can compactly represent the relationship among variously sized numbers. This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is… … Wikipedia
Orders of magnitude (energy) — Different orders of magnitude of natural energy production for solar, wind and geothermal versus average global consumption rate (1 W = 1 J/s) This list compares various energies in joules (J), organized by order of magnitude. List of orders of… … Wikipedia
List of languages by number of native speakers — For various estimates of the total speakers of the top dozen languages, see List of languages by total number of speakers. Current distribution of human language families For larger map, scroll towards end of article. The following tables list… … Wikipedia
Demographic history of Poland — Main article: Demographics of Poland Historical demography of Poland shows that in the past, Poland s demography was much more diverse than at present. For many centuries, until the end of Second World War, the Polish population was composed of… … Wikipedia
ROM — read only memory; rough order of magnitude … Military dictionary
COCOMO — Not to be confused with Docomo or Kokomo. The Constructive Cost Model (COCOMO) is an algorithmic software cost estimation model developed by Barry W. Boehm. The model uses a basic regression formula with parameters that are derived from… … Wikipedia
Kelvin–Helmholtz mechanism — The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. As a result of this cooling, the pressure drops, and the star or planet compresses to compensate. This compression, in turn, heats … Wikipedia
COCOMO — (Constructive Cost Model) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
Cocomo — (COnstructive COst MOdel) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
ROM — • Read Only Memory Nur Lese Speicher • Range Of Motion (medical) • Rough Order of Magnitude • Rome Metropolitan Area, Italy internationale Flughafen Kennung … Acronyms
rough order of magnitude
Смотреть что такое «rough order of magnitude» в других словарях:
rough order of magnitude — n. Fancy way of saying to make a wild [ass] guess … Business English jargon and slang
Orders of magnitude (numbers) — The logarithmic scale can compactly represent the relationship among variously sized numbers. This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is… … Wikipedia
Orders of magnitude (energy) — Different orders of magnitude of natural energy production for solar, wind and geothermal versus average global consumption rate (1 W = 1 J/s) This list compares various energies in joules (J), organized by order of magnitude. List of orders of… … Wikipedia
List of languages by number of native speakers — For various estimates of the total speakers of the top dozen languages, see List of languages by total number of speakers. Current distribution of human language families For larger map, scroll towards end of article. The following tables list… … Wikipedia
Demographic history of Poland — Main article: Demographics of Poland Historical demography of Poland shows that in the past, Poland s demography was much more diverse than at present. For many centuries, until the end of Second World War, the Polish population was composed of… … Wikipedia
ROM — read only memory; rough order of magnitude … Military dictionary
COCOMO — Not to be confused with Docomo or Kokomo. The Constructive Cost Model (COCOMO) is an algorithmic software cost estimation model developed by Barry W. Boehm. The model uses a basic regression formula with parameters that are derived from… … Wikipedia
Kelvin–Helmholtz mechanism — The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. As a result of this cooling, the pressure drops, and the star or planet compresses to compensate. This compression, in turn, heats … Wikipedia
COCOMO — (Constructive Cost Model) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
Cocomo — (COnstructive COst MOdel) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
ROM — • Read Only Memory Nur Lese Speicher • Range Of Motion (medical) • Rough Order of Magnitude • Rome Metropolitan Area, Italy internationale Flughafen Kennung … Acronyms
rough order of magnitude
Смотреть что такое «rough order of magnitude» в других словарях:
rough order of magnitude — n. Fancy way of saying to make a wild [ass] guess … Business English jargon and slang
Orders of magnitude (numbers) — The logarithmic scale can compactly represent the relationship among variously sized numbers. This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is… … Wikipedia
Orders of magnitude (energy) — Different orders of magnitude of natural energy production for solar, wind and geothermal versus average global consumption rate (1 W = 1 J/s) This list compares various energies in joules (J), organized by order of magnitude. List of orders of… … Wikipedia
List of languages by number of native speakers — For various estimates of the total speakers of the top dozen languages, see List of languages by total number of speakers. Current distribution of human language families For larger map, scroll towards end of article. The following tables list… … Wikipedia
Demographic history of Poland — Main article: Demographics of Poland Historical demography of Poland shows that in the past, Poland s demography was much more diverse than at present. For many centuries, until the end of Second World War, the Polish population was composed of… … Wikipedia
ROM — read only memory; rough order of magnitude … Military dictionary
COCOMO — Not to be confused with Docomo or Kokomo. The Constructive Cost Model (COCOMO) is an algorithmic software cost estimation model developed by Barry W. Boehm. The model uses a basic regression formula with parameters that are derived from… … Wikipedia
Kelvin–Helmholtz mechanism — The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. As a result of this cooling, the pressure drops, and the star or planet compresses to compensate. This compression, in turn, heats … Wikipedia
COCOMO — (Constructive Cost Model) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
Cocomo — (COnstructive COst MOdel) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
ROM — • Read Only Memory Nur Lese Speicher • Range Of Motion (medical) • Rough Order of Magnitude • Rome Metropolitan Area, Italy internationale Flughafen Kennung … Acronyms
What Is the Rough Order of Magnitude (ROM) and How Is It Calculated?
During the project initiation phase (or when you are preparing for a project management exam) you will likely come across the term rough order of magnitude (ROM). The PMI’s Project Management Body of Knowledge refers to the rough order of magnitude as an initial estimate in the “estimate cost” process (source: PMBOK®, 6 th edition, part 1, ch. 7.2). As the book does not elaborate on the details of the ROM, you might be wondering how it is defined and determined – especially as it is relevant for the PMP exam. The short answer is:
Read on to learn more details and background. If you wish to calculate the ROM range for an initial estimate, use this free ROM calculator.
What Is the Rough Order of Magnitude (ROM)?
The rough order of magnitude (ROM) is a type of cost estimate that is used in various kinds of projects. These include but are not limited to strategy development and implementation projects, IT projects as well as construction projects. It is typically used in the preparation and initiation phases of projects for the development of a project business case, for instance, or for the determination of the required financial resources that are stated in the project charter.
The accuracy of ROM estimates is -25% to +75% according to the PMBOK (source: PMBOK®, 6 th edition, part 1, ch. 7.2). Other authors set the range at +/-50% which can be used as an alternative in practice if the estimate is deemed conservative.
Illustration of the use of ROM and definitive estimate in different project phases for cost estimating purposes.
To narrow this wide range of possible outcomes down, this rough cost estimate is expected to be refined in the course of the project as more information and better estimates can be obtained over time (similar to the concept of progressive elaboration).
It shall then be replaced with a so-called definitive estimate that is much more accurate (see below section on the differences between both estimates).
How Is the ROM Determined?
The calculation of the rough order of magnitude range is relatively straight forward. The formulas for the calculation of the upper and lower boundaries are as follows:
Upper Boundary = ROM_Estimate x (1 + 75%) = ROM_Estimate x 1.75;
Lower Boundary = ROM_Estimate x (1 – 25%) = ROM_Estimate x 0.75.
In practice, the more challenging part is usually to come up with the ROM estimate (i.e. the basis for the ROM range) rather than calculating the boundaries of that range. It can be determined using established estimation techniques such as analogous or parametric estimates.
As the ROM is typically used for projects in the initiation phase with a high level of ambiguity and uncertainty with respect to the expected cost, the required input data for these techniques may not be available though. The same holds true for the option to involve subject matter experts: they might not be assigned or available for bottom-up estimating at the time of a project’s initiation.
The initial estimate is therefore often based on high-level expert judgment, sometimes in conjunction with three-point estimating.
What Is the Difference between Definitive Estimate and Rough Order of Magnitude?
There are three key differences between the ROM and the definitive estimate:
Comparison of the accuracy ranges of rough order of magnitude (ROM) and definitive estimate.
This is because the rough order of magnitude is typically determined in the initiation phase of projects (or parts of projects) when information that is required for proper estimating tends to be vague. Resources, as well as data, may also be limited. The definitive estimate, on the other hand, is calculated in subsequent project phases when these constraints are broadly resolved.
Thus, the definitive estimate can be computed using more accurate estimation techniques, such as bottom-up estimation or parametric estimates. Both may not be available at the time the ROM estimate is determined.
Conclusion
The rough order of magnitude estimate is a rather inaccurate type of project cost estimate. However, it is typically used in the initiation phase of a project when the available information and resources do not suffice to produce better estimates.
In this situation, the ROM provides at least a rough idea of the cost range of projects which is often useful for the purpose of stakeholder communication in an early stage. The ROM estimate can also be used to develop a project business case or a project charter, for instance.
If you wish to learn more about cost and time estimating, read our guide to estimating costs take a look at our other articles on this topic.
rough order of magnitude
Смотреть что такое «rough order of magnitude» в других словарях:
rough order of magnitude — n. Fancy way of saying to make a wild [ass] guess … Business English jargon and slang
Orders of magnitude (numbers) — The logarithmic scale can compactly represent the relationship among variously sized numbers. This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is… … Wikipedia
Orders of magnitude (energy) — Different orders of magnitude of natural energy production for solar, wind and geothermal versus average global consumption rate (1 W = 1 J/s) This list compares various energies in joules (J), organized by order of magnitude. List of orders of… … Wikipedia
List of languages by number of native speakers — For various estimates of the total speakers of the top dozen languages, see List of languages by total number of speakers. Current distribution of human language families For larger map, scroll towards end of article. The following tables list… … Wikipedia
Demographic history of Poland — Main article: Demographics of Poland Historical demography of Poland shows that in the past, Poland s demography was much more diverse than at present. For many centuries, until the end of Second World War, the Polish population was composed of… … Wikipedia
ROM — read only memory; rough order of magnitude … Military dictionary
COCOMO — Not to be confused with Docomo or Kokomo. The Constructive Cost Model (COCOMO) is an algorithmic software cost estimation model developed by Barry W. Boehm. The model uses a basic regression formula with parameters that are derived from… … Wikipedia
Kelvin–Helmholtz mechanism — The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. As a result of this cooling, the pressure drops, and the star or planet compresses to compensate. This compression, in turn, heats … Wikipedia
COCOMO — (Constructive Cost Model) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
Cocomo — (COnstructive COst MOdel) ist ein algorithmisches Kostenmodell, das in der Softwareentwicklung zur Kosten bzw. Aufwandsschätzung verwendet wird. Mit Hilfe von mathematischen Funktionen wird ein Zusammenhang zwischen gewissen Softwaremetriken und… … Deutsch Wikipedia
ROM — • Read Only Memory Nur Lese Speicher • Range Of Motion (medical) • Rough Order of Magnitude • Rome Metropolitan Area, Italy internationale Flughafen Kennung … Acronyms