IB Business Management HLTopic 5 — Operations ManagementPaper 1 & 2Core idea~10 min read
Job, Batch, Mass and Flow Production
A wedding dress and a bottle of cola are both “made”, but nobody makes them the same way. The production method a business picks decides its unit cost, how quickly it can change its mind, and how skilled its workers need to be. Get the method wrong and the business is either too expensive or too rigid to survive.
📚 What you need to know
Job production — one item at a time, made to the customer’s own specification.
Batch production — a group of identical items goes through each stage together, then the line is reset for the next batch.
Flow (mass) production — a continuous line of identical items, each moving from workstation to workstation.
Mass customisation — a standard base built on a flow line, with customer choices bolted on.
As you move from job to flow, unit cost falls but flexibility falls too.
The choice depends on output volume, how standardised the product is, capital available and what customers are buying on.
The one idea behind all four methods
Every method is a position on the same slider. At one end you make one thing for one person; at the other you make a million identical things for a million people. Everything else — cost, skill, machinery, lead time — follows from where you sit on that slider.
If you can only remember one thing about this topic, remember the direction of the slider. Almost every evaluation point comes from the cost-versus-flexibility trade.
Job production
One product, made from start to finish for one customer, to that customer’s own specification. Think of a made-to-measure suit, an architect designing a single house, or a garage repairing a specific fault.
Why it costs so much. Nothing is repeated, so the business cannot spread its set-up time or learn shortcuts. It usually needs skilled staff who can handle whatever the order asks for, and skilled staff are expensive. There are almost no economies of scale, because bulk buying is impossible when every order needs different materials.
What it buys in return. Exactly what the customer asked for. That justifies a premium price, and it builds loyalty, because the customer was part of the design. Lead times are long, which is fine if the customer expects to wait for something special — and fatal if they do not.
Watch for the trap. Job production does not mean “made by hand”. A shipyard building one tanker is job production and it uses enormous machinery. What defines it is that one unit is made to one customer’s specification.
Batch production
Here a group of identical items moves through the whole process together. All 400 white shirts are cut, then all 400 are stitched, then all 400 are pressed. Only when the batch is finished does the business reset the machines for the next batch, perhaps 400 blue shirts.
Batch sits in the middle for a reason. Because items within a batch are identical, the business gets some of the speed and bulk-buying savings of a production line. Because batches can differ from each other, it keeps some choice — a bakery can make sourdough on Monday and rye on Tuesday.
The cost of that middle position is changeover time. Every reset between batches means machines standing idle, workers waiting and cleaning down. That idle time is pure cost, and it is why batch producers try to run long batches even when demand does not really justify it. The other issue is stock: finishing 400 shirts at once means storing 400 shirts until they sell.
A neat exam sentence: “batch production trades flexibility for changeover time.” If a case study mentions frequent product changes or idle machinery, that is the point the examiner is fishing for.
Flow (mass) production
A continuous line of identical products, each moving from one workstation to the next, with each station doing one small job. Nothing waits for a batch to finish; as soon as a unit leaves station one, the next unit arrives.
The red line is the killer disadvantage. A flow line has no slack in it, so a single breakdown, strike or late delivery halts everything downstream.
Why unit costs collapse. Machines run without stopping, so there is no changeover time. Each worker repeats one simple task and gets fast at it. Materials are bought in enormous quantities, so suppliers discount them. Fixed costs like the factory building are spread across a huge number of units. That is economies of scale in action.
Why it is risky. The line costs a fortune to build, so the business is committed. It only pays back if demand stays high. And it produces one thing — if tastes change, the equipment cannot easily be repurposed. Add the motivation problem: repeating one task for eight hours is dull, which raises absenteeism and labour turnover.
Mass customisation
Mass customisation is the attempt to have both ends of the slider. The business builds a standard platform on a flow line, then lets each customer choose from a menu of options that get added as the unit moves along.
A car maker is the obvious example. Every car on the line shares the same body shell and engine family, but this one gets leather seats and a tow bar while the next gets cloth seats and a roof rack. The customer feels they designed something; the business keeps most of its economies of scale.
It only works with modern technology — computer-controlled machinery that can switch settings between units, and software that keeps every customer’s order matched to the right shell as it moves down the line. That technology is expensive, which is the main evaluation point against it.
Do not confuse mass customisation with job production. In job production the customer can ask for anything. In mass customisation the customer picks from a fixed list of options. The difference is who sets the limits.
Comparing the four methods
Feature
Job
Batch
Flow / mass
Volume
One at a time
Groups of identical units
Continuous, very high
Unit cost
Highest
Middle
Lowest
Flexibility
Total
Some, between batches
Very little
Worker skill
High, broad skills
Mixed
Often low, narrow tasks
Capital needed
Low to medium
Medium
Very high
Main weakness
Slow and expensive
Idle time at changeover
One breakdown halts everything
Typical example
Made-to-measure suit
Bread, paint, medicines
Bottled drinks, phones
How a business chooses
🧩 Four questions that decide the method
How many units will we sell? Low volume rules out a flow line, because the line will never be busy enough to pay for itself.
How standardised is the product? If every customer wants something different, job or batch is forced on you.
Do we have the capital? A flow line is a huge upfront investment. A start-up usually cannot fund one.
What are customers buying on? If they are buying on price, chase low unit cost. If they are buying on individuality, chase customisation.
Businesses grow along the slider. A firm often starts with job production, moves to batch as orders repeat, then to flow once demand is reliable. That “as the firm grows” framing is a strong way to structure an evaluation answer.
Worked examples
WORKED EXAMPLE 1
A small brewery makes four different beers. Each is brewed in 2,000-litre runs, then the tanks are cleaned before the next beer. Identify the production method and explain one drawback for this brewery. [4]
Step 1: match the clue to the method
Identical units made together in a group, then a reset before the next group.
This is batch productionStep 2: one drawback, applied to this brewery
Cleaning the tanks between beers is changeover time. During it the tanks produce nothing, so the brewery pays for equipment and staff that are earning no revenue, which raises the cost per litre.
Notice the answer names the actual changeover (cleaning tanks) rather than saying “there is downtime”. That is the applied mark.
WORKED EXAMPLE 2
A furniture maker currently uses job production and has a two-month waiting list. It is considering switching to batch production. Recommend whether it should. [10]
Step 1: the case for switching
Batch would cut lead times and unit costs, letting the maker serve the waiting customers before they go elsewhere and possibly widen the market by lowering price.
Step 2: the case against
Its customers may be paying a premium precisely because each piece is unique. Standardising into batches removes that, so the firm could lose its pricing power and its point of difference.
Step 3: judgement
It depends on why the waiting list exists. If customers are waiting happily, the queue is evidence of a strong brand and switching destroys it.
Recommend a partial switch: batch-produce a small standard range, keep job production for bespoke ordersA recommendation that keeps both options alive is fine, as long as you justify it and say what would change your mind.
💡 Exam tip
Look for the clue word in the stem. “Made to order” means job. “Runs of” or “before the next” means batch. “Continuous” or “assembly line” means flow.
Every advantage has a matching cost. Low unit cost comes with rigidity; customisation comes with a high price. Pair them in evaluation.
Bring in unit cost figures if the case study gives them. A calculated cost per unit before and after is far stronger than a description.
Do not forget the workers. Flow production affects motivation, and Unit 2 theories (Herzberg, Taylor) give you extra depth here.
Say what the business sells on. Price-led firms go right on the slider; quality-led or bespoke firms stay left.
⚠️ Common mix-up
Batch is not “a few units”. A batch can be 100,000 tablets. What matters is that the group moves through each stage together.
Flow production is not automatically automated. A line can be run by people. Automation is a separate decision.
Mass customisation is not full customisation. The choices come from a fixed menu.
Economies of scale are not the same as “cheap”. They are the fall in average cost as output rises — you must say average cost, not total cost.
Job production is not always small-scale. Bridges and cruise ships are job production.
Up next: Lean Production and Cutting Waste — how a business squeezes cost out of whichever method it has chosen.
Want this explained one-to-one?
Book a free session with an experienced IB Business Management tutor and get your trickiest topics made simple.
