Implementation is the stage where the new system replaces the old one. The method chosen decides how much risk the organisation takes, how long the changeover lasts and how much extra work staff must do.
This lesson follows designing an input form and comes before evaluation, inside the ICT applications and system lifecycle module.
What are the methods?
| Method | What happens | Main advantage | Main risk |
|---|---|---|---|
| Direct | Old system stops, new one starts at once | Fast and cheap | If it fails, there is nothing to fall back on |
| Parallel | Both run together for a time | Safe; results can be compared | Double the work; costly |
| Pilot | New system used in one place or by one group first | Problems found on a small scale | Other places wait; slower |
| Phased | New system introduced one part at a time | Staff learn gradually; easier to fix | Takes longer; old and new must work together |
Pilot and phased are often confused. A pilot tests the whole system in one location. Phased brings in one part of the system everywhere.
How do you choose?
Ask about the case:
- How serious is a failure? Hospital or payroll data suggests parallel or phased.
- How big is the organisation? Several branches suggest a pilot.
- How skilled are the staff? Low confidence suggests a gradual change.
- Is the old system reliable enough to keep running? If not, direct may be the only option.
Worked example
Invented case: Three branches of a clinic (fictional) will move from paper appointment books to an electronic booking system. Each branch holds about 400 patient records.
Step 1, size the work: 3 branches × 400 records = 1,200 records to enter. At 40 records per hour that is 1,200 ÷ 40 = 30 hours of typing in total, so 10 hours per branch.
Step 2, weigh risk: a lost appointment inconveniences patients, so a direct start is risky.
Step 3, choose: a pilot at one branch first, so any fault shows up in 400 records, not 1,200. If it works, the other two branches follow.
Step 4, justify: “A pilot limits the damage if the booking software has faults, and staff at the other branches can learn from the first.”
The mistake to watch for
Mistaken answer: “Parallel running suits because it is the safest.”
The case has three branches and a small staff. Running two systems doubles the workload and is expensive.
The correction is to name the cost along with the benefit: “Parallel is safest, but double entry for 1,200 records is a heavy extra burden, so a pilot suits better.”
Check yourself
1. A one-person bakery (invented) is replacing its till and the old one has broken. Which method is likely and why?
Show answer
Direct. The old system cannot be kept running, and with one user the risk and training load are small.
2. Is rolling out only the payroll section of a new system to all branches first a pilot or phased?
Show answer
Phased. One part of the system goes to every branch. A pilot would give one branch the whole system.
3. Give one disadvantage of parallel running.
Show answer
Staff must do the work twice, which takes extra time and money.
Where this leads next
After a system has been introduced, it is judged against what was asked for: evaluate a system against its original requirements. Refresh the starting point in extracting user requirements if you need to.
If case-style comparisons are costing you marks, our team’s online one-to-one ICT tuition can practise them with you.