Scheduling

In time management, scheduling is part of scheduling and deals with the planning of appointments and work processes . The result of the scheduling is the schedule .

General

Appointments determine the everyday life of all economic subjects who have to differentiate between internal and external appointments. External appointments are agreed with other economic entities such as due dates , delivery times , negotiations or payment deadlines . Appointments consist of a calendar date , a time and a start and end date that can extend over a longer period of time. There are internal appointments as the start and end date for the execution of tasks , usually without an end date for meetings , works meetings or business meetings . In the serial and mass production specific methods are used ( scheduling ), but determining date is a necessary routine. It is based on production planning and control systems (PPS), which are regularly closely linked to resource planning and material supply planning . In the service sector scheduling also plays an important role such as in doctors' offices or hospitals.

In private law, dates are a specific point in time at which something is supposed to happen or a legal effect occurs by itself, or in procedural law a point in time for litigation that is precisely determined in advance by the court . Important features of planning in business administration are the planning object , planning subject , planning data and planning period. The objects of planning in scheduling are the work processes and fixed dates, the planning subjects are the workers responsible for scheduling , planning data are all information relevant to the dates and the planning period can be a project that lasts for years .

If a business entity has to observe several dates at the same time, scheduling is helpful. Scheduling is a central part of corporate planning. It is an essential part of work preparation and aims to schedule the work flow. Its aim is to coordinate several appointments in such a way that they do not collide with one another. Any unexpected delays in appointments should be planned so that the sequence of appointments is not disrupted and there is no time pressure during an appointment .

Organizational flow

Comprehensive scheduling particularly requires the construction industry , shipbuilding and plant engineering , which are therefore examined as examples for all branches of the economy . The starting point for scheduling is the individual work process, the time required to complete it is the process duration. The milestone, such as the completion of the shell or the building acceptance, is without a duration . The organizational, physical or technical dependencies between the individual work processes must be taken into account in the process planning. The duration of the process and the schedule together make up the schedule. Follow-up dependencies must be taken into account, because activity B can only begin and thus become part of the schedule when activity A has been completed. In addition, there are production processes in which work processes are not arranged one after the other, but overlapping or parallel to one another.

species

With regard to the purpose of scheduling, a distinction is made between production- oriented and project-oriented scheduling . The project-oriented scheduling aims at the coordination of all those involved in the project, while the production-oriented one takes into account the capacity planning , the personnel deployment ( personnel deployment planning ) and the use of production material given the given lead times .

Capacity or resource planning

The capacity or resource planning is closely related to the scheduling, since a shortening of the project time can usually only be achieved if the capacities or resources are increased sufficiently. A distinction must be made between the following capacities (resources):

• Capacities of commercial staff including subcontractors,
• Device capacities,
• Material capacities,
• Capacity in planning and project management as well
• financial resources (guarantees, bridging loans or cash).

Histograms and graphs for the individual resources can be derived directly from the schedule .

Forward or backward termination

There is also forward (progressive) or backward (retrograde) scheduling, depending on whether the earliest start date or the known end date is specified. The backflush scheduling is based on the specified end date and calculates all dates and their duration in order to be able to infer the start date.

Phases

In the case of larger construction plans, the structuring of the project ( project structure plan ) and thus the definition of the processes to be planned must be carried out carefully. The aim is to record all relevant processes in a hierarchical structure and at the same time to limit oneself in such a way that only the project-relevant processes are listed. This task is often also called work package creation (WBS, Work Breakdown Structure), in which the project is structured down to the relevant individual tasks.

The scheduling of larger projects is carried out in several phases. There are three phases in construction:

Framework or rough schedule planning

The framework or rough schedule is used for general project planning. This includes relatively few, but higher-level processes (mostly 20 to 50). The time dimension is months or quarters.

Coordination or control scheduling

The term coordination scheduling is usually used by building contractors, the term control scheduling by project managers. This planning stage comprises several hundred to several thousand processes. The coordination or control schedules include the planning (planning of the planning) and / or the construction in detail. The time dimension is days.

Detailed scheduling

The detailed scheduling includes the planning of project areas. It rarely comprises more than 100 activities. The time dimension is days or hours. Typical examples are cycle planning, weekly or two-week planning for foremen and foremen, planning for particularly critical processes or planning for compensating for delays in appointments.

Outside of construction, a distinction is often made between

• Project Scheduling : The term "project" here in the sense of not still present order used. The project scheduling is used to represent a potential time processing before a customer task becomes an order,
• Order scheduling : For an order from a customer, it begins after the contract is signed.

Tools for scheduling

Organizers , appointments diaries or calendar programs (such as Microsoft Project ) are available as tools for scheduling . The existing deadlines and other deadline-relevant work processes must be entered and updated.

In general, every scheduling, both every method and every representation, can be carried out manually. This can still be appropriate today if, for example, a computer with installed scheduling software is not available.

In principle, IT-supported scheduling uses different tools:

• CAD programs that are used for this purpose as pure drawing programs. The advantages compared to a traditional display of pen and paper include the ability to change it quickly and the high quality of the display.
• Standard software for office applications (office packages) with spreadsheets and presentations are not designed for professional scheduling, but are still widely used for scheduling. These programs lack many functionalities that provide dedicated scheduling programs and thus make work much easier. One disadvantage, for example, is that deadline controlling is not supported by such software.
• Dedicated project management software packages
  • Paid software to be licensed
  • Free project management software
• For special applications are used:
  • Graphics packages for improved visualization of data
  • Time management programs,
  • Scheduling for medical practices, group practices and hospitals
  • Appointment planning for hospitals, specialist and rehabilitation clinics as well as medical supply centers (MVZ) with integrated medical paths for interprofessional, interdisciplinary and intersectoral treatment planning, case and resource management.

presentation

Representation types according to DIN 69900 are bar plan , line diagram , network plan and the appointment list . The scheduling should floats include the unexpected delays ( English job stopper ) into account and thus not threaten the Endfertigstellungstermin.

Appointment list

With a list of dates, individual partial services are recorded chronologically with the start and end dates. In the appointment list, the processes with the planned appointments are arranged in a table. The appointment list is clear and has the advantage that it can be printed out on a DIN A4 sheet and easily sent by fax. It is also used to report actual appointments as part of appointment controlling.

Bar plan

The most widespread bar chart (also called Gantt chart ) contains the required time units on a time axis and the associated activity on the ordinate, and is very clear thanks to a time-proportional representation. With the bar chart, the activities are written one above the other in one column. The duration of the process is represented true to scale by a bar that is positioned along the horizontally plotted time axis. The tasks are usually sorted in such a way that the tasks that start early are at the top and those that start late at the bottom. This makes the bar plan very clear. It is the most frequently used display and is characterized by a good overview. In the bar chart, within the framework of a simple schedule controlling, the actual point in time is often shown by a vertical line (thread with plumb line) and the progress made is shown within the bar by markings.

Path-time or line diagram

A path-time or line diagram is a special representation of the construction process at line construction sites (e.g. roads, tunnels, sewer construction, pipeline construction). The stations of the construction site are plotted on the abscissa. The time axis runs downwards. The course of individual work and equipment groups is represented by a line. The line thus represents the speed at which the machine or work group works its way along the construction site. Slightly inclined lines indicate a high speed, while heavily inclined lines indicate low speeds.

Network plan

→ Main article : Network plan technique

The network plan links work processes using process relationships. With the network plan technique, the

• Forward scheduling the earliest dates and at the
• Backward scheduling calculates the latest dates.

The critical path calculation is made from the latest and earliest dates. These indicate the extent to which processes can be postponed without affecting the earliest position of subsequent processes or the planned completion of the entire project. The network plan technique is for very complex projects, e.g. B. moon landing , suitable.

Methods and approach

A distinction must be made between heuristic and mathematically analytical methods. With the heuristic methods, the processes are arranged according to experience in such a way that a plausible schedule is created. A typical representative is the bar plan. The network plan technique represents the mathematical analytical method. It is based on a mathematical-analytical procedure based on graph theory .

The framework or rough schedule is part of a project development (setting the project goal) and must therefore be carried out in parallel with the commercial (financial framework), technical, legal and ecological project definition.

The coordination schedule is created by the contractor (construction company) after the order has been placed. The client (building owner) is well advised to set up a similarly detailed schedule himself to follow the construction progress. Since he is often not able to do this, he will commission a project manager to do this .

Detailed schedules are drawn up for

• Cycle planning
• Planning of particularly critical project phases (e.g. expansion of an old bridge and lifting of a new building over a motorway with partial closure at the weekend)
• Weekly planning for foremen and
• Planning to catch up on delays within a limited period of time.

Deadline control and deadline monitoring

Erich Gutenberg already pointed out in 1958 that scheduling and scheduling must be organized differently in the individual branches of industry according to the manufacturing processes used. In flow production , scheduling is essentially work cycle planning ; in large-scale production , scheduling can be largely standardized. Deadline control is one of the three basics (deadline, cost and quality control ) for controlling production or a project. Dates that are not certain (such as contractually agreed delivery times) are included in the scheduling as a “target date” on which a certain work process should be completed so that a subsequent one can begin. The actual completion is the "actual date"; Delays occur when the "actual dates" are after the "target dates". The appointment control should ensure that there are no delays.

Deadline controlling

Deadline controlling represents a process that runs repeatedly in the same way in the sense of a cybernetic control loop . This consists of the following sub-steps:

• Creation of a schedule that defines the planned project sequence as a target (construction target, English baseline ).
• Recording of the actual project status (Bauist, English actual ) at a specified date.
• Eventually recording of deadline risks as a percentage and / or as a beam for the actual status and forecast.
• Carrying out a deviation analysis in which it is determined where relevant differences exist between the target and the actual. As a rule, there are numerous small target / actual deviations, but these are of no importance. The result of variance analysis is regularly in a progress report ( English progress report ) documents.
• The schedule controller then determines with the project management which control measures are to be taken to compensate for the relevant deviations. A distinction must first be made between who is responsible for the deviations: client or entrepreneur. There may also be so-called "neutral" deviations. In the construction industry, neutral deviations can be, for example, strikes or exceptional weather conditions that the contractor did not have to expect when the contract was signed. In such a case, it is usually contractually stipulated that the construction period will be extended. Measures to compensate for delays in deadlines can include, for example: increasing staff and / or equipment capacity, overtime and weekend work, other construction methods (e.g. prefabricated parts instead of in-situ concrete) or the use of subcontractors. If the deadline controlling is delayed due to cumbersome procedures when coordinating control measures, this can cause consequential damage for which the controlling may be liable.
• If necessary, the schedule (construction target) must be adjusted.

At the beginning of the project, the project management must determine the rhythm at which the schedule controlling process will be carried out, for example weekly, monthly or quarterly. The rhythm is based in particular on the entire project duration and the project size. Controlling can be carried out weekly for short-term and small projects. Projects that run over several years and are very large (e.g. planning and building a power plant) can possibly be set to a quarterly rhythm. For typical construction projects, controlling should be carried out every two weeks or at least once a month. Only if the controlling intervals are sufficiently short compared to the overall project time can schedule deviations be countered with reasonable effort.

It is also important to define in the project who has which powers of attorney in the event of discrepancies, to threaten and, if necessary, initiate sanctions against those responsible for the discrepancies, e.g. termination of the contract.

Expediting is a special case of deadline controlling .

purpose

In addition to being a planning instrument , scheduling also serves to control , monitor , monitor and document the workflow. It is intended to ensure that future internal and external appointments are recognized in good time and adhered to. This promotes the impression of punctuality and reliability in other economic agents and contributes to the fulfillment of the legal principle “contracts must be kept” ( Latin pacta sunt servanda ). In polychronic cultures, punctuality only plays a subordinate role, appointments or schedules are of no importance.

Individual evidence

1. ↑ REFA Association for Work Studies and Business Organization e. V. (Hrsg.): Methodology of the operational organization: Lexicon of operational organization . Munich: Carl-Hanser, 1993, p. 181, ISBN 3-446-17523-7
2. ↑ Gerhard Köbler , Etymological Legal Dictionary , 1995, p. 405
3. ↑ Günter Wöhe , Introduction to General Business Administration , 2013, p. 63
4. ^ Fritz Berner / Bernd Kochendörfer / Rainer Schach, Fundamentals of Construction Management 2: Construction Management Planning , 2013, p. 36
5. ↑ Bert Bielefeld, Basics Scheduling , 2008, p. 8
6. ↑ Bert Bielefeld, Basics Scheduling , 2008, p. 10
7. ↑ Bert Bielefeld, Basics Scheduling , 2008, p. 9
8. ↑ Bert Bielefeld, Basics Scheduling , 2008, p. 11
9. ↑ Tanja Kessel / Marcel Gawlitta / Corinna Hilbig / Martina Walther (Eds.), Aspects of Construction Management in Research and Practice , 2015, p. 249
10. ^ Bert Bielefeld / Thomas Feuerabend, Baukosten- und Scheduling , 2007, p. 98
11. ↑ Bert Bielefeld, Basics Scheduling , 2008, p. 12 f.
12. ↑ Christian Zanner / Birthe Saalbach / Markus Viering, rights from disrupted construction process according to claims , 2014, p. 14
13. ↑ Christian Zanner / Birthe Saalbach / Markus Viering, rights from disrupted construction process according to claims , 2014, p. 5
14. ↑ Christian Zanner / Birthe Saalbach / Markus Viering, rights from disrupted construction process according to claims , 2014, p. 6
15. ↑ Christian Zanner / Birthe Saalbach / Markus Viering, rights from disrupted construction process according to claims , 2014, p. 9
16. ↑ Erich Gutenberg, Introduction to Business Administration , 1958, p. 65
17. ↑ Tanja Kessel / Marcel Gawlitta / Corinna Hilbig / Martina Walther (eds.), Aspects of Construction Management in Research and Practice , 2015, p. 250