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A pdf of the complete Praxis Comparative Glossary can be downloaded here.


Fron Near critical activity to Overload


Near critical activity

An activity with little float that could become part of the critical path with a slight delay. This could potentially make a significant change to the sequence of activities that form the critical path.

Near critical activities should be monitored closely. What is classed as ‘near’ is up to those managing the project. It will depend upon the general length of activities and volatility of the schedule.

Negative float

Where a path in a network diagram becomes supercritical the activities on that path have float of less than zero, i.e. negative float. The quantity of float then indicates the amount of time that must be picked up in order to achieve an imposed date.



Negotiation is a collective term for various mechanisms that seek to resolve differences between individuals, groups or companies. Its goals are to:

  • find solutions to issues involving two or more parties;
  • develop beneficial relationships between two or more parties.

The principles of negotiation are used in many different contexts. Two obvious applications are in conflict management and procurement.

The APM BoK also includes the negotiation function. It is not a subject covered by PRINCE2 or ISO21500. The PMBoK mentions it briefly as a tool used in the Acquire Project Team and Conduct Procurements processes.

Net cash flow

In discounted cash flow techniques this is the net income/expenditure in a particular year that is multiplied by the relevant discount factor to give the discounted cash flow, i.e. the value of a future year’s net income or expenditure at today’s prices.

Net present value

The present value of a future income less the initial capital investment.

Network analysis

A generic term for the various techniques of analysing network diagrams including PERT/Time, PERT/ Cost, Monte Carlo analysis and critical path analysis.

Network diagram


Networks diagrams are, in effect, method statements in pictorial form. They represent the way that activities will be performed in order to achieve the objectives. These techniques were first used in the 1950’s and variants were simultaneously developed on both sides of the Atlantic.

There are two main formats for preparing a network diagram: activity-on-node (the most common form of which is the precedence diagram) and activity-on-arrow. Both formats achieve the same result but since 1985 precedence has become by far the more widely used, mainly due to the widespread use of scheduling software.

Network path

A sequence of interconnected activities in a network diagram.


A generic term for events in an activity on arrow diagram and activities in a precedence diagram.

Nominal group technique


A form of collective decision making.

There are numerous situations where a P3 manager needs to collate ideas from a group of individuals and arrive at a decision. It may be a group of stakeholders discussing benefits, a project team identifying major risks or a technical team debating alternative technical solutions.

Nonaka and Takeuchi


Ikujiro Nonaka and Hirotaka Takeuchi1 set out their spiral model of knowledge management in 1995. Sometimes known as the ‘SECI model’ it addresses the links between tacit and explicit knowledge and illustrates how knowledge is expanded and enhanced through the process of converting tacit knowledge to explicit knowledge and back again.


  1. Nonaka, I., Takeuchi, H., (1995), The knowledge creating company: how Japanese companies create the dynamics of innovation, Oxford University Press, New York.

Non-financial measure of benefit

A measure of a benefit that enables it to be measured but not in financial terms.

Non-splittable activity

An activity that must not be split during resource limited scheduling.

Normal distribution

A statistical distribution that is symmetrical about the mean. The project duration calculated by PERT analysis is assumed to be the mean of a normal distribution. This enables ranges of completion dates and their probabilities to be calculated.

For example, there is a 99.7% probability that a project will finish between ± 3 standard deviations from the mean.

Normal resource limit

The preferred limit for resource availability when performing resource levelling.

See also maximum resource limit.


The third stage of team building in the Tuckman model.

Not earlier than

A form of imposed date placed on an activity that indicates that it may not start or finish earlier than the specified date.

Not later than

A form of imposed date placed on an activity that indicates that it may not start or finish later than the specified date.


The objectives of a project or programme are what is required to be delivered. Objectives can be defined in terms of outputs, outcomes or benefits or any combination of the three.


A PRINCE2 term that refers to a situation where a product does not (or is not forecasted to) meet the specification laid out in the product description. It is also used in the case of a missing product.

Operational costs

Costs expended on operational resources as opposed to those expended on capital investment.

Operations management

A function in the APM BoK that describes the management of business as usual. This is considered to be out of scope by the other guides.


A risk event that could have a positive effect on the project or programme. Historically, the term risk has usually been seen as possible threat to the objectives of the project or programme but uncertain events can also be potential opportunities which have their own set of opportunity responses.

Opportunity response

There are four ways of responding to an opportunity (positive risk event). These are:


Find a way of maximising the positive effect of the opportunity.


Work with a partner or supplier to maximise the positive effect of the opportunity.


Find a way of increasing the probability of the opportunity occurring or the impact it will have.


Reject the opportunity as being unworthy of further action.

Optimistic cost

The optimistic estimate of cost for use in PERT/Cost.

Optimistic duration

The optimistic estimate of an activity’s duration for use in PERT analysis or Monte Carlo analysis.


The comparison of different options for a project or programme in order to determine which is the best value.

OR relationship

A type of dependency link between activities in a probabilistic network.

OR relationships can take two forms. An inclusive OR relationship is where any or all of the preceding or succeeding activities may occur. An exclusive OR relationship is where only one of the preceding or succeeding activities may occur.

Order of magnitude estimate

An initial high level estimate intended to give an indication of project cost. The precise meaning of order of magnitude varies widely but typically, it may represent a variance on the estimate of ±40%. This type of estimate is usually the first step in top down estimating.

Ordinal date schedule

Ordinal numbers are 1, 2, 3. Therefore ordinal dates would be day 1, day 2, day 3.

Cardinal numbers are 1st, 2nd, 3rd. Therefore, cardinal dates would be 1st February, 2nd February etc.

Sometimes a schedule is prepared using ordinal dates when a start date is not known. Starts and finishes are then expressed in terms of ‘day 47’ or ‘week 17’.

Organisation management


Organisation management is concerned with creating and maintaining a management structure applicable to the project, programme or portfolio and the context in which it operates. Its goals are to:

  • design an organisation appropriate to the scope of work to be managed;
  • identify and appoint members of the management team;
  • maintain and adapt the organisation throughout the life cycle.

In PRINCE2 the element of this topic that deals with the management team is covered by the organisation theme, in the PMBoK® guide it is the project human resource management knowledge area and in ISO21500 the resource subject group.

Organisation management plan


The organisation management plan sets out the preferred procedures, tools and techniques to be used in organisation management.

Organisational ability

The capability of an organisation to perform the work in an MSP 5th Ed. programme with its current resources.

Organisational capacity

The amount of work that an organisation can deliver effectively in any given period of time.

Organisational culture

An unwritten set of rules that influences the attitudes and behaviours  of individuals and groups. Cultures exist at all levels from the top of the organisation through portfolios, programmes, projects and teams.

APM BoK 7 has a dedicated topic on the subject.

Organisational breakdown structure

A breakdown structure that shows a hierarchical representation of the management team and delivery team of a project, programme or portfolio.

Organisational Process Assets

An all-encompassing term used by the PMBoK® guide for a project’s plans, processes, policies, procedures and knowledge bases.

Organization (PRINCE2 theme)

The organisation theme addresses the design and creation of the project management structure, including definition of roles and responsibilities.

This theme also covers stakeholder management.

Praxis has an organisation management topic and also a dedicated topic for stakeholder management.

In ISO21500 the equivalents are the resource and stakeholder subject groups. The PMBoK® guide equivalent knowledge areas are project human resource management and project stakeholder management.

Organization (MSP theme)

The theme that describes the organisation management of a programme on a role by role basis. It replaces the MSP 4th Ed. topic called programme organisation.

Original duration

See baseline duration.

Out of sequence logic

The GAO SAG term for out of sequence progress.

Out of sequence progress

When an actual start date is entered against an activity that’s predecessor has not yet been completed the progress is out of sequence with the logical dependencies.



One of the three types of objective of a project or programme.

An outcome is a change in working practices that result from using an output. An outcome should lead to measurable benefits as it becomes part of business as usual.

Outline business case

In the first phase of the project life cycle, there will not be sufficient information available to develop a detailed business case. Typically, an outline business case will be included in a project brief. This should justify the project sufficiently to warrant the investment in more detailed planning.

In Praxis the outline business case is developed during the identification process, in PRINCE2 it is developed during the Starting Up a Project (SU) process. In MSP 5th Ed. it is developed during the Identify the programme process



There are two common uses of the term:

Firstly, an output may simply be the output of a management process, e.g. the brief is an output of the identification process in Praxis.

Secondly, an output is one of three ways of defining the objectives of a project or programme. In this context it is a product or combination of products that are created by a project.

Output rate

Data that enables a planner to estimate the duration of an activity, e.g. cubic metres per hour for an excavator or bricks per hour for a bricklayer.


See lead time and lag time.


The amount of resource required by the project schedule which exceeds the resource limit.



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