What planning predicts

What good planners do differently

The clearest behavioural signature of good planning comes from the Tower of London itself. In a study of healthy adults, better performance went with longer preplanning time and shorter execution time, and good performers increased their preplanning more sharply as problems got harder than weaker planners did. In other words, strong planners front-load their thinking and then move cleanly. Weaker planners start sooner and do their thinking on the board, one correction at a time.

Patients with frontal-lobe damage show the other side of this. On a computerised tower task they needed more moves, and although their thinking time before the first move was normal, their thinking time after the first move was significantly longer. They were not skipping the plan; they were building it piecemeal, mid-solution. Our session report for Towers of London tracks the same distinction as a "thinking before moving" ratio where your timing data allows it.

Expertise shows up too. Regular chess competitors, who spend years calculating move sequences, outperformed matched people who do not take part in chess on the Tower of London, most clearly on the hardest problems, with no difference between the groups in fluid intelligence or working memory. They were also slower, taking longer to plan and to execute. That is a useful reminder that careful planning costs time, and that on untimed or lightly timed tasks the time is usually well spent.

Planning and academic outcomes

The best large-sample evidence on planning and school achievement comes from the Cognitive Assessment System (CAS), a standardised test built around the PASS model (Planning, Attention, Simultaneous and Successive processing). Its Planning scale correlates moderately with academic achievement, around r = .49 to .57 in the test developers' data. A follow-up analysis of 2,036 children and teenagers found that the three CAS planning tasks kept improving until at least age 15, and that their link with achievement looked remarkably similar for maths and reading, which suggests a general rather than subject-specific benefit.

Two cautions. The CAS "planning" tasks are timed tasks that reward an efficient strategy, not tower puzzles, so they are a cousin of what our games measure, not the same thing. And a correlation of .5 means planning explains roughly a quarter of the variation in achievement, not all of it.

Planning at work

There is no large meta-analysis that links tower-puzzle scores directly to job ratings; we looked and could not find one. The closest evidence comes from two directions.

The first is everyday planning behaviour. A 2021 meta-analysis of 158 studies of time management, which covers scheduling, prioritising and planning one's time, found moderate positive links with job performance and academic achievement. It also found something every exam candidate should notice: time management was barely related to scores on standardised tests.

• Job performance (21 studies)0.26
• Academic achievement (76 studies)0.26
• Grade point average (57 studies)0.21
• Standardised test scores (7 studies)0.01

That last bar makes sense. Organising your weeks helps you do the work that raises grades; it does not by itself make you better at a timed reasoning paper. The cognitive side of planning, the look-ahead that tower and maze tasks measure, is a different ingredient.

The second is general mental ability, of which planning-style reasoning is one part. A classic review of 85 years of personnel research put cognitive ability among the strongest predictors of job performance, especially in combination with a work sample or structured interview. A 2022 reanalysis argued those older estimates were inflated by over-correction, cut the mean validities of the top-ranked methods by .10 to .20, and concluded that the methods remain useful, just less predictive than once thought. Planning tasks inherit this picture: useful, but not magic.

Executive functions more broadly are linked to many life outcomes. Diamond's review lists poorer productivity and difficulty finding and keeping a job among the consequences of weak executive functions.

The planning fallacy: planning's blind spot

Being able to plan a puzzle does not protect you from misjudging your own projects. In the study that named the effect, students predicted they would finish their theses in an average of 33.9 days. The average actual time was 55.5 days, and only about 30% finished by their own prediction. The authors showed that people build predictions from a mental scenario of the plan going well, and neglect their own past experience. When students were made to connect their predictions to relevant past experiences, the optimistic bias disappeared.

For placement season this matters practically. Your preparation plan will almost certainly take longer than you think. Plan with the outside view: how long did the last mock test series actually take you?

What a planning score can and cannot tell you

It mixes abilities. When researchers asked what predicts Tower of London performance, fluid intelligence was the only significant predictor among the measures they tested. Executive functions are not the same as general intelligence, but tower tasks load on both. A low planning score can reflect slow reasoning, a lapse of attention, or plain unfamiliarity with the format.

Problem difficulty is more than move count. The minimum number of moves is not enough to rate a tower problem. How clear the goal's stacking order is, how the start position is stacked, and how many optimal paths exist all change how hard a problem feels. Our generator controls several of these (see the Towers of London lesson).

Reliability is moderate. A carefully balanced Tower of London problem set reached split-half reliability of .72 and internal consistency of .69: good for research, but it means a single short session is noisy. Executive tasks also tend to have low test-retest reliability, because performance can jump the moment someone discovers a better strategy.

That last point cuts both ways. It means your first attempts at a planning game underestimate you, and it means practising the format before a real assessment is legitimate. It does not mean the underlying ability has changed. Lesson 4 deals with what practice can and cannot do.

What this means for you

Put the evidence together and a sensible attitude follows.

• Planning is worth training, but it is one ingredient. Its links with grades and job performance are moderate, not decisive. Treat a planning game as one section of your preparation, alongside numerical, verbal and logical practice.
• One score is a noisy snapshot. With reliabilities around .7 and strong practice effects, a single low result says more about that day and your familiarity with the format than about your ceiling. Judge yourself on trends across several sessions.
• Speed is rarely the point. The best planners in the research were slower to start and faster to finish. On a move-limited game, a longer first pause is usually a good sign, and our scoring reflects that by giving time only a small weight.
• Your own schedule is a planning task too. The planning fallacy applies to placement preparation as much as to theses. Build slack into your study plan, and base it on how long things actually took you before.

The next lesson shows where in the recruitment process you will meet planning, and in what form.

2 practice questions

1. In the time-management meta-analysis, which outcome was essentially unrelated to time management?
2. Frontal-lobe patients in Owen and colleagues' tower study showed normal thinking time before the first move. What was different?

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Sources

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