Reverse-engineering II — the Introduction and the gap
Week 5 · 2105620 Research Communication Skills for Chemical Engineers
3 September 2026
Three hours, and one sentence to leave with
Today
- 12 min What we need from the last two weeks — and nothing else
- 23 min The Introduction as five moves
- 25 min Activity 1 — label the moves
- 10 min Debrief
- 10 min Break
- 25 min Absence is not a gap · claim strength
- 25 min Activity 2 — your gap in three sentences
- 15 min Debrief
- 10 min Break
- 15 min From gap to aim to Methods
- 10 min Activity 3 · close
What we need from the last two weeks
12 minutes · and then we leave it alone
Two ideas. One from the matrix, one from the recordings. If you missed either, you are not behind after the next ten minutes.
From Week 3 — three shapes of gap
The one thing the matrix was for
| Two rows contradict | An unresolved question |
| A column is empty for every row | Nobody has measured it |
| Every row shares one condition | The field has tested only one regime |
A gap is a property of a table, not a feeling you get while reading.
From Week 4 — an Introduction is five moves
The one thing the recordings were for
- Establishes a context the reader already accepts
- Narrows once or twice, each time tighter
- Reports what is known — and then what is not
- States the gap — as a cost, not as an absence
- States an aim the Results can answer
Five moves, in this order. Almost every published Introduction has all five. The ones that fail usually fail at four.
The five moves
Block 2 · 23 minutes
Now the same five moves, slowly, and where each one fails.
Move 1 — establish something they already accept
Where the reader stands
- Good — a fact of the field nobody argues with. Emissions are large. Zinc is cheap. The reader nods and reads on
- Bad — a claim you will have to defend. Now the reader is arguing before you have said what you did
- Also bad — so general it belongs in any paper. “Energy storage is important” opens ten thousand papers a year
One paragraph. Sometimes two sentences. The commonest fault is that it goes on for a page.
Move 2 — narrow, and mean it
The funnel
Field → approach → the specific system you work on
- Once is often too fast. Four times is a review article
- Each narrowing must exclude something. If nothing is excluded, it is not a narrowing
- Narrowing twice to the same place is the commonest structural fault in a draft Introduction
Move 3 — known, then not known
Two moves that look like one
| What is known | The state of the art, with numbers. What has been achieved, and by roughly what means |
| What is not known | Where that work stops. Not everything it fails to do — the one thing your paper is about |
Most drafts do the first and skip the second, then jump straight to the aim. The reader is never told why the aim is worth pursuing.
Move 4 — the gap
The move everything today is about
An absence is a fact
about the literature.
A gap is a claim about what that absence costs us.
What the difference looks like
Same field, two sentences
| ✗ Absence | Comparatively little work has been done on the degradation of blended amine solvents |
| ✓ Cost | Because degradation rates for blended solvents are not reported under realistic flue-gas conditions, the operating cost of a retrofit cannot be estimated before it is built |
The second sentence tells a reviewer why to fund it. The first tells them a search returned few results.
Move 5 — an aim a result can answer
The test
| ✗ | to understand the mechanism of ___ |
| ✗ | to investigate the behaviour of ___ |
| ✓ | to determine which of four ___ sustains ___ at ___ |
| ✓ | to establish whether ___ changes when ___ |
Name the measurement that would tell you whether you achieved it. If you cannot, it is not yet an aim.
Label the moves
Activity 1 · 25 minutes · the sheet in front of you
What to do
Activity 1
- 8 minutes alone. Six paragraphs on the sheet. Write what each one does — ten words, verb first
- 7 minutes in pairs. Compare. Where you disagree, decide which of you is right
- Then the three questions at the foot of the page
The paragraphs were written for this exercise. They are not a real paper — do not cite them and do not go looking for them.
What you found
Debrief 1
- P2 and P5 do the same job. Both narrow to post-combustion amine scrubbing. The argument walks back up the funnel and down it again
- P6 states an absence, not a gap. “Little work has been done” — on its own that is a fact about a search
- The aim cannot be settled. “To better understand the degradation mechanisms” — name the measurement. There isn’t one
Three faults, six paragraphs, no chemistry required to find any of them.
10
Break · back at the time on the board
Absence is not a gap
Block 3 · 25 minutes
The same three shapes from your matrix, turned into sentences a reviewer can act on.
Three shapes, three sentences
From the table to the page
| Two rows contradict | *Reports disagree on whether . Under X the effect is , whereas under Y ___* |
| A column is empty | No study to date reports ___ under ___ conditions |
| One shared condition | Existing work is confined to ; behaviour under remains uncharacterised |
Each of these is defensible, because the table is the evidence. “Little work has been done” is defensible only until somebody runs your search.
But that is still only half a gap
The second half
- What is known — it is established that ___
- What is not known — what has not been ___ is ___
- What that costs us — because of this, we cannot ___
Sentence three is the one that is missing from almost every draft I read, and it is the only one a reviewer cares about.
How strong is your claim, exactly?
Hedging
| is | Measured directly, in this work |
| indicates | Measured, and the reading points one way |
| is consistent with | Not measured. Compatible with what was |
| suggests | Inference from someone else’s result |
| may | Speculation, and labelled as such |
Overclaiming is the fastest route to a hostile review. Underclaiming loses you the contribution. The verb has to match the evidence exactly.
Your gap, in three sentences
Activity 2 · 25 minutes · your own topic
What to do
Activity 2
- 10 minutes alone. Three sentences on your own area. Known · not known · what it costs. No reading, no searching
- 10 minutes in pairs. Swap sheets. Ask the two questions printed under the box
- 5 minutes. Rewrite yours after your partner has finished with it
No topic yet? Use the area your laboratory works in. Nobody is committing to anything today.
Sentence three, out loud
Debrief 2
Read me sentence three only.
- The room decides: a cost, or an absence wearing longer words
- “Has not been systematically investigated” is an absence with a suit on
- If it names something we cannot do, predict, or explain — it is a gap, and it is yours
10
Break · back at the time on the board
From gap to aim to Methods
Block 4 · 15 minutes
The gap decides the aim. The aim decides what the Methods have to contain.
The chain
Each link constrains the next
Gap → Aim → Method → Result
- The gap says what we cannot currently do
- The aim says what this paper will settle — in terms a measurement can close
- The method must contain something that produces that measurement
- The result must report it. Every aim, one answer
Week 4 called the broken version an orphan aim: promised on page two, abandoned by page nine. This chain is how it happens, and where to catch it.
Operational definitions
Where two papers stop being comparable
| Failure | At 80 % of initial capacity? At a short circuit? At a voltage threshold? |
| Efficiency | Averaged over all cycles, or measured at the end? |
| Stable | Over what duration, and within what band? |
This is why cells in your matrix would not fill last week. Not carelessness — a missing definition in somebody’s Methods.
One aim sentence
Activity 3 · 7 minutes
Turn your gap into an aim a result could settle. Name the measurement.
Before Week 6
Three things
- Keep this sheet. Week 7 builds a manuscript blueprint and it starts from your three sentences and your aim
- Assignment 1 and the Week 4 outline — if either is still outstanding, submit before Sunday. No penalty
- The evidence map — 10 to 15 sources, due before Week 7. Start it from the four rows you already have
Week 6 · 10 and 13 September — Reverse-engineering III: Methods, Results, and evidence.
Before you go · 45 seconds
How was today?
Five questions. Anonymous — no name, no email, no login.
The fourth question is the one I actually use.
The two most common answers open next week’s session.
oxidized-challenge-ed9.notion.site
Scan now — I will wait