What Is Parallel Running? 11 Facts You Need To Know

Parallel running is a system transition approach in which a new system gradually acquires the roles of an older system while both systems operate concurrently. This changeover takes happen when the previous system’s technology is obsolete, necessitating the installation of a new system.

What Is Parallel Running?

 Parallel running is an approach for system transition in which a new system gradually inherits the responsibilities of an older system while both systems operate concurrently. The previous system’s technology has become obsolete, necessitating the installation of a new system in its place.After a period of time during which the system has been proven to function properly, the old system will be fully eliminated and users will rely only on the new system.What Is Parallel Running?The term parallel running can apply to either the process of migrating a portion of a business’s information technology operations to a new system or the method used by human resources departments in which the current staff remains on board while the transition to a new staff.

Understanding Parallel Running

After the new system has been developed and tested, it must be implemented so that it can perform its duties effectively and in accordance with the goals. This requires the following initial steps:

  • Verifying that the appropriate hardware and software have been prepared; preparing and storing any additional hardware and software prior to their implementation. The hardware and software must be inspected for problems prior to installation.
  • This comprises people who will operate the new system as well as those who will support others throughout the initial phases of deployment, including the Network Administrator and supervisors.
  • Data must be entered into the data files of the new system either manually or by downloading them from the old system.

To implement the new system, a parallel running strategy in which the new system is run concurrently with the old system for a set period of time can be implemented. Parallel running and parallel processing are two distinct concepts.

In addition to the aforementioned implementation methodologies, there are more options available. There are advantages and downsides to each of the implementation options. Therefore, the application of a particular implementation method depends on the organization’s requirements.

The process Of Parallel Running

During changeover, a new system and an existing system operate concurrently for a predetermined amount of time. This should be lengthy enough to guarantee that all components of the new system have been thoroughly tested and proven to function properly.

Both enter the same data and execute the same operations. This will demonstrate the reliability of the new system by comparing their output.

If the new system is approved, the current system will cease operation and be replaced by the new system. If both the old and new systems are computerized, the input data can be stored on a disk or tape and executed simultaneously on both systems.

The most difficult aspect of transitioning from a manual system to a digital system is entering the data. Data must be entered manually, which might take a considerable amount of time.

Advantages Of Parallel Running

Parallel execution permits the comparison of outcomes to confirm that the new system is error-free.

What Is Parallel Running?

If errors are discovered, the user can refer to the old system to remedy the issue and modify the new system, allowing operation to continue under the old system while the issues are resolved. This also permits staff training and helps employees build trust in the new system.

Disadvantages Of Parallel Running

Due to the need to operate the two systems concurrently, the implementation cost is astronomical. Electricity and operating expenses are extremely expensive. A vast and intricate system would make this impractical. Parallel installation also necessitates a significant amount of time and regular maintenance.

In order to attain the same goal for both systems, employees will need to double their typical workload for a period of time, which will slow down output. This requires entering or modifying the same data in both systems to guarantee that the data are identical.

Examples of parallel running implementation

Job placement is a concrete illustration of parallel running in human resource management. Both new and existing workers do the same duties. If the performance of the new staff is satisfactory, the current employees may become obsolete and be replaced.

Another instance is when a new company that has undergone a change in ownership seeks to hire new employees to operate the company. If the new employees do not know the fundamentals of the operation, implementing the change all at once can generate complications.

For this reason, the company will retain the existing workforce for a specific period of time to continue performing their regular duties while the new hires shadow them and gain the necessary hands-on experience.

Once the productivity and operational outcomes of the new employees match those of the existing staff, the existing staff can be terminated. Parallel running is utilized by numerous businesses to ensure that their computer program is capable of performing its intended functions.

The business firm provides identical input to both the old and new software. After a period of time, the outputs of both software applications are compared to ensure that the transition to the new system is flawless.

An further example is a publishing house that produces textbooks. They plan to invest in a new computerized accounting system to manage the accounting department. The existing account system is obsolete and cannot be utilized with modern devices.

All accounts and invoices must be processed in both the new and old systems, as the new system is implemented utilizing a parallel running technique. If the new system fails to function properly, the old system’s data can be utilized.

However, because everything must be completed twice, the accounting department will be slowed down and must hire additional people at a cost. This system is secure, and the new system can be carefully checked, as the results of each transaction can be compared with those of the previous system.

What Is Parallel Running?

It is also used when a new computerized system is used to establish quick reference records and generate orders, but the old manual method is maintained for ultimate financial control until it is confirmed that the new system functions properly.

Post-implementation review

The post-implementation review phase typically lasts between three and six months after the implementation of a new system. The aim of the review is to:

  • Determine if the aims of the new system have been reached; if the new system is operating differently from the stated objectives, the problems must be identified and the new system must be modified further. This is to ensure that the new system is capable of doing the tasks for which it was created.
  • Ensure that users are using the system properly; reports should serve their intended purpose.
  • Certify that the system is maintained and adaptable; Additional enhancements and functionalities can be added to the new system.
  • Determine the weaknesses in the development process in order to improve future systems; prevent repeating previous errors

Other methods of implementation

Parallel Running is complemented by direct switching, phased implementation, and pilot running. When a direct changeover occurs, the old system is instantly removed and replaced with the new system.

This is a hazardous alternative because there may still be issues with the new system. It is the most affordable and straightforward method of transition, but if something goes wrong, the user cannot revert to the previous system.

Before the new system goes live, the entire staff must receive thorough training and all files must be inputted. In phased implementation, the system is gradually implemented. Parts of the old system are replaced while the remainder of the old system continues to operate.

A school, for instance, was implementing a Management Information System for all elements of its operations. It could implement the enrollment system, the examination system four months later, and the timetabling system four months after that.

As each new module is activated and its functionality is confirmed, the subsequent module can be added. It is conceivable that certain modules will be compatible with one another. For instance, the timetable module assumes that all student information is available, thus the sequence in which they are introduced must be considered.

Pilot running is the installation of a new system for a limited number of users to test and assess the new system. The new system is introduced for all users once it has been determined that it has been thoroughly tested and can function properly.

The test users can help train others on how to operate the new system. This implementation technique is extremely beneficial for a system with a big number of users, as it ensures that all users can properly utilize the system.

Human-computer considerations

The transition from a manual to a digital system might result in organizational reorganization. People’s standing and position might fluctuate. These modifications can influence employees’ perceptions of their employment, safety, authority, and interactions with coworkers.

People’s reluctance to adopt a new computer system may be attributable to the system’s failure to fulfill specific job requirements, security concerns, the possibility of data loss, apprehensions about making mistakes while using the system, and adverse health impacts.

Similarly, computerized systems can influence the management function and decision-making process of managers. Users are more likely to accept user-friendly systems because they feel familiar with the system, have a sense of control, and can analyze their stored input data.

The system should also be sufficiently adaptive to accommodate users of various backgrounds and skill levels. Overcoming resistance to change and implementing the new system is a managerial challenge.

What Is Parallel Running?

This may be modified by system-related attitudes and expertise of human-computer interaction. Therefore, communication skills are essential to persuade individuals of the advantages of the new system.

People should have the chance to learn and assess the system. Once they have witnessed and experienced the advantages of the new system, they will be more willing to embrace and operate it.

Education and training of staff

The manner in which systems are operated impacts the implementation’s success. Considering the scale and complexity of the system, multiple levels of education and training for using the system are possible. Personnel and personnel must be educated about the system’s general information architecture and operation.

This will provide an overview of the system in place and how information is managed within the organization. In order to identify which training requirements must be met, it is necessary to determine the organization’s information system infrastructures.

Information system managers, system operators, and support employees are required by businesses with complicated systems involving operations between regional offices via network and distributed system.

The employees will require training in the operation of equipment and support services in order to effectively address difficulties.

In small organizations where information systems are managed by departmental computers and software, employees may also be responsible for managing computer systems. This may be the case if the organization’s systems were created by end-users or with the help of application packages.

Various training courses pertaining to the information systems of the organization are accessible. Frequently, software companies and universities offer generic training courses, with much reliant on organizational needs and the location of training centers.

In addition to providing product- or system-specific training, a given product’s supplier also gives training. Many organizations that provide software have training departments whose primary function is to support clients. Typically, training can be given at the supplier’s location, or the organization can opt for in-house training, which takes place at its own facilities.

It is necessary that the operators and users of the new system receive training to ensure proper operation. Therefore, the expense should be considered as an investment in the organization’s ability to achieve its objectives.

Parallel Run Testing

What does parallel run testing mean?

If you are new to the world of payroll, “parallel run testing” may sound scary. However, performing parallel runs merely entails running your old payroll software alongside your new payroll software and comparing the results, hence the term.

In order to provide an accurate portrayal of how the new system will work during regular payrolls, the payroll cycles you specify for this type of test should reflect normal payroll cycles.

Choosing to test irregular payroll cycles with unusual changes, such as multiple wage hikes or new hiring, may enhance the probability of inaccuracy. Consequently, it is essential to keep things simple.

How do you carry out parallel run testing?

Parallel run testing is theoretically straightforward, albeit it takes careful attention to detail. To do a parallel test, you must take the following steps:

  • The previous supplier should export all pertinent data for a specified payroll period. This information includes tax and benefit information.
  • The exported data must then be imported into the new payroll system.
  • The new system should be used to process payroll.
  • The new system’s results can then be compared to the old system’s results in order to identify and resolve any inconsistencies.

Who should carry out parallel run testing?

Since the new payroll system will be used moving forward, the parallel runs are typically performed by the company’s payroll administrator. If an accountant or bookkeeper handles your payroll, they should perform the parallel runs. This not only provides an opportunity for hands-on training, but also aids in identifying any flaws in the new system before it goes live.

What Is Parallel Running?

Nonetheless, concurrent runs increase the payroll administrator’s job. During this changeover phase, additional support from individuals inside the organization or from the new provider’s support staff may be beneficial. Payroll businesses have conducted thousands of installations; therefore, you should not be hesitant to seek their counsel regarding parallel run testing.

How many payrolls should be tested?

Parallel testing often employs two payroll cycles. To guarantee that any errors are identified, corrected, and then re-run, it is recommended to run these two payroll cycles sequentially.

Obviously, each firm is unique; therefore, the best time and method for parallel testing may vary from one business to the next.

How should you handle discrepancies?

After one payroll cycle of parallel testing, it is time to line-by-line compare the findings of the new and old systems. If a disparity is observed, it should be documented, highlighted, and then categorized according to the error’s source. Common sources of inconsistencies include the following:

  • Entry errors
  • Old system errors Differences explained (ie. rounding errors)
  • Rule creation-attributable errors
  • Unexplainable errors

As soon as discrepancies are identified, they must be resolved. Once the error has been rectified, additional parallel run testing should be conducted to generate more precise results. If failures that cannot be explained remain, you should continue to perform parallel tests until these problems are fixed.


This method is not as concerned with the change’s long-term repercussions. It is just a mechanism for ensuring that there is no disruption in company flow while new processes replace old ones.

With a smooth transition and the new implementation operating concurrently with the old standard, any concerns about the change’s viability can be allayed.


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