Mass claims and collective actions: two different ways of tackling the same legal problem

When one and the same event, contract, product or business conduct affects many people at once, the impression may arise that we are necessarily faced with a single collective dispute. The fact that there are hundreds or thousands of similar claims does not, however, mean that in law there is a single claim, or that the appropriate procedural response must always be a joint one.

The distinction matters because it shapes the strategy entirely. Managing a large portfolio of individual claims in a coordinated way is one thing; bringing an action designed to protect collective interests is another. Both may start from a common problem, but they answer to different legal and procedural logics.

1.Many people affected do not necessarily mean a single dispute

Suppose a product has apparently caused similar harm to numerous users. There may be a common question as to its design, manufacture or marketing. Each injured party, however, may have suffered different harm, may have used the product differently, may present circumstances of their own or may have different evidence as to the causal link.

The existence of a potentially common cause does not necessarily remove the individual character of its consequences.

Something similar happens with certain contractual disputes. One and the same clause may appear in thousands of contracts, yet each customer's position may vary as regards performance, the payments made, later correspondence, the amount at stake or even the version of the contract that applies.

The common legal question may coexist with facts and consequences that require individual treatment.

This distinction is particularly important when the defence or the pursuit of large groups of matters is to be organised. Before deciding how to manage them, it is necessary to know which part of the dispute genuinely belongs to all of them and which part remains specific to each case file.

2.The difference between a volume portfolio and a collective action

Volume legal case management makes it possible to work with precisely that duality.

There may be a common strategy on a central legal question while an individual case file is kept for each person affected. General documents, certain arguments, technical reports or negotiating criteria can be shared, while each claim retains its own facts, its own evidence and its own circumstances.

This model has significant advantages where homogeneity is high but not absolute. It makes it possible to draw on the knowledge gained in some cases, to maintain consistent criteria and to cut down repetitive work without dispensing with the analysis of those differences capable of altering the outcome.

Collective redress answers to a different logic. Its purpose is not simply to process many matters together, but to protect interests with a common or collective dimension by means of the instruments laid down by the law.

In the consumer field, European law has strengthened this kind of redress through representative mechanisms that allow action to be taken against certain conduct harming a plurality of people. The existence of these instruments does not, however, mean that every high-volume phenomenon must necessarily be channelled through them.

The decision depends on the nature of the problem, on the homogeneity existing among those affected, on the aim pursued and on the type of redress sought.

3.Separating the common questions from the individual ones

This is probably the first major decision in any potentially high-volume portfolio.

It is necessary to identify which questions can be analysed once and projected onto all the case files and which require individual evidence or assessment.

In civil liability the distinction is especially clear. There may be a common event giving rise to liability and one and the same legal question as to liability. But the harm suffered by each injured party may be different. Causation, the personal or financial consequences and the available evidence may also vary.

The existence of a common origin does not allow the individual analysis of the loss to be dispensed with automatically.

Something similar may happen in insurance. One and the same type of insured event may affect numerous insured parties, but the cover, the limits, the specific circumstances or the documents available may vary. Even within a single portfolio, different policies or contractual terms may coexist.

The strategy must carefully separate the two levels.

There may be a common legal basis, a shared technical analysis or one and the same reading of the contract. But each case file must retain those variables capable of altering its individual outcome.

This approach avoids two opposite mistakes. The first is to study, hundreds of times over, a question that is genuinely identical. The second is to assume that a general conclusion automatically resolves every case file.

4.Coordinated management makes it possible to draw on shared knowledge

When the structure is properly designed, each case ceases to be an isolated compartment.

A legal question can be analysed in depth once and made available to the whole portfolio. A common technical report can serve to understand the general origin of a problem. A particular reading of the contract can be applied consistently across every case file to which it is applicable.

This makes it possible to concentrate resources on the genuinely variable parts of the matter.

Technology is especially helpful for this structure. It can keep common documents accessible from every case file and at the same time preserve the documents specific to each one. It can identify which matters share certain features and which display differences.

In this way, a change in legal judgement can be projected rapidly onto the whole affected group. And an individual issue can be kept confined to the case file to which it belongs.

Nor does the classification have to remain unchanged throughout the life of the portfolio. It is possible that at the outset we consider there to be two broad types of matter and that the first cases reveal a third category that had not been identified initially.

Flexible management must allow that learning to be incorporated.

5.The first decisions should not be read automatically

The way the initial cases develop can provide very valuable information.

A judgment may clarify a common legal question. An objection may bring to light an argument that had not been sufficiently weighed. Expert evidence may reveal that certain case files ought to be separated from the rest.

But conclusions must be drawn with care.

A favourable decision in one matter does not necessarily guarantee the same outcome in all the others. It may turn on specific facts or evidence. Nor does an unfavourable decision necessarily mean that the general strategy is wrong, if the problem lay solely in the documents of that particular case file.

That is why it is not enough to record whether a case has been won or lost.

One must understand why.

Knowledge management requires identifying which part of the court's reasoning can be carried over to the rest of the portfolio and which part belongs solely to the particular case.

This distinction allows the first decisions to improve the strategy without giving rise to excessive or mistaken reactions.

6.Scale also has an economic dimension

The cost of handling numerous matters individually may prove disproportionate if each case file requires every step to be reproduced by hand.

Standardisation makes it possible to reduce that cost and to make it viable to pursue or defend situations which, taken in isolation, might show an inefficient relationship between the amount at stake and the professional effort involved.

But economic efficiency should never determine the legal solution on its own.

It may be very cheap to produce hundreds of identical claims and extremely costly to correct, afterwards, hundreds of claims built on a mistaken premise.

That is why the initial work of analysis is especially important in volume cases. The greater the volume, the greater the value of defining the criterion correctly before beginning to apply it.

A distinction must also be drawn between a common strategy and a common outcome. Two case files may be correctly managed under the same criterion and end differently because of their facts, their evidence, a negotiation or the court's decision.

Homogeneity seeks to ensure that equivalent situations receive equivalent treatment. It does not mean that they must all necessarily produce the same end result.

7.Choosing the right instrument requires first understanding the problem

The expression mass claims essentially describes a reality of volume. Collective redress corresponds to a specific legal way of addressing certain common interests.

Confusing the two ideas may lead to a badly designed strategy from the outset.

The relevant question is not simply how many people are affected. What must be determined is what they genuinely have in common, which questions can be resolved jointly and which elements continue to depend on individual circumstances.

On the basis of that answer it can be decided whether it is appropriate to use a collective instrument, to manage a portfolio of individual claims under common criteria or to combine different strategies for different dimensions of the dispute.

Volume case management adds value precisely because it allows work to be done between those two extremes. We can deal jointly with the knowledge, the documents and the criteria that are genuinely common, while preserving the individual character of those facts and that harm which require an analysis of their own.

The aim is not to turn many disputes into a single one. It is to prevent the existence of many case files from forcing us to study repeatedly what we already know, while at the same time not losing what makes each of them legally different.

Alburquerque Abogados|José Manuel Alburquerque|Barcelona 23/07/2026

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