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What makes a great one page note

This is part of a series of "what makes a great.." notes to help people who are interested in copying the 2050 calculator. They are ideals, which the UK calculator may not live up to.

Once the assumptions have been gathered and a proposed set of levels 1-4 developed, the next step is to document these in detail (as we have done in the 2050 pathway reports and this wiki) and in summary as a one page note.

A great one page note:

  1. Briefly summarises the sector, and the situation today
  2. Briefly sets out the meaning of levels 1-4, and the key implications of that level of deployment
  3. Illustrates the levels, ideally by comparing the deployment to historical levels or deployment in other countries
  4. Illustrates the levels with a bar chart showing the amount of energy that sector produces or uses. This bar chart should have the same scale across every one page note, so one page notes can be compared with each other.

These one page notes should be checked with stakeholders who have different opinions of the sector to make sure they support what it says.

Previous: What makes a great sector workshop

Next: What makes a great sector worksheet

The original DECC one page note writing guide


Try to get a buddy to read your drafts before they go to someone else for formal checking or approval. Your buddy can give you friendly feedback about clarity and style and also check for typos. This will improve the quality of the draft before it is checked more formally and save time for the approver.


  • Every sentence must be true.
  • The meaning must be clear.
  • Be brief.


  • Define abbreviations before or straight after first use on a page. Use very few abbreviations.


  • Don't use an adjective or adverbs when a number would do (grows 1 GW a year, not grows slowly)
  • Use a hyphen when using a number as an adjective. for example, "x is equivalent to 50 2-MW wind turbines,"
  • Take care when using adjectives or adverbs that involve a judgement call:
  • Slowly, slow, slower
  • Lags
  • Imaginable
  • Ambitious
  • Challenging
  • Exponentially
  • Sustained
  • Small, smaller
  • Slightly
  • Large
  • Broadly similar (just use similar)
  • Considerably
  • Most
  • Potential, potentially

Stick to numbers rather than making judgements.


  • Third person, not I or We
  • For the one pagers, past tense for 2007. Future tense for 2010+. When describing a future trajectory that depends on assumptions, always make clear that dependence, so the reader doesn't think we are saying "x will happen". Rather write, "At level 2, x will happen". Context may make it clear so including assumptions is not always essential but please err on the side of repeating the statement of assumptions rather than not.


  • Include cross-references.
  • Cross-reference to a page number


  • Put heading on top, including units


  • Put the information in context by stating current energy use/power:

◦for the UK as a whole, in GW and in TWh/year ◦in kWh/person/day

  • Try to pick a comparator that is similar to the thing you are comparing. For instance, compare future offshore wind capacity to today's offshore wind capacity, rather than today's total wind capacity. For instance, compare electricity produce by a power station with total electricity produced in the UK rather than with the electricity consumed in a home. For instance, compare distance travelled by car each year in the UK with the distance between two UK cities rather than with the distance to the moon or around the equator.
  • Make comparisons with physical things (e.g., number of 750 kW Pelamis Wave machines)
  • When comparing a large figure to a small figure, don't bother with excessive accuracy on the small figure (e.g., "Capacity reaches 140 GW in 2050, compared with less than 1 GW in 2007" rather than "...compared with 0.0151 GW in 2007")


  • Comparing energy or power with a number of homes
  • Comparing distance with number of times round the earth, or distance to the moon
  • For the one pagers, comparisons with other levels (e.g., don't say level 4 is 10% greater than level 3)
  • Comparing power output of, for instance, wave with that of wind. Let the TWh charts at the bottom of the page do that.


  • Compare with the same number in the past (plot a trend)
  • Consider helping the reader by giving a factor (e.g. "which is 30 times 2007 levels")
  • Compare with the same number in another country (especially countries that are models of that technology - eg Japan for heat pumps, Germany for wind, Sweden and Germany for insulation)
  • Compare area with the size of the UK, by plotting both on a map of the UK


  • Numbers greater than (roughly) ten should be written in digits not words ("3000" not "three thousand")
  • Numbers should have units
  • Put a consistent space (half-space for the one pagers) between numbers and their units
  • Don't use excessive accuracy ( e.g., 3 GW rather than 3.0GW unless we know we are accurate to within +/- 0.05 GW)
  • For the one pagers, don't use a 000 separator, use a half space (e.g., 100 000 not 100,000) Numbers of four or less digits do not need a space separator. 100; 999; 1000; 1111; 10 000; 10 001, etc.
  • Be consistent with units. In the one page notes, we are using:

Energy TWh Power GW Area km2 Emissions CO2e Mass bn t, Mt Freight t-km Fuel consumption mpg AND litres per 100 km Distance m, km


  • How many things would need to be built (e.g., 10 000 750 kW Pelamis wave machines). Make sure this clearly states the size of the thing (e.g., 750 kW)
  • How many would need to be built per year (e.g., 10 000 cavity walls would need to be insulated each year)


  • Typically, the most important assumptions are: area; amount of energy captured


1.Top: Explanation of the subject and the situation in 2007 2.Then: Explanation of the levels, starting with 1, with title for each level 3.Then: Chart comparing with history or other country 4.Then: Where relevant, explain link to other choices 5.Right: Relevant map or Picture 6.Bottom: Chart showing TWh/yr in 2007 and for different levels


  • Don't repeat what levels 1, 2, 3, 4 mean
  • Do repeat information across one page notes - Don't assume they will be read in sequence.
  • Don't imply a fact when we are explaining an assumption: Avoid will, won't and instead say "assumes that" (e.g., "Level 4 assumes that we individually won't be travelling as much" rather than "We individually won't be travelling as much")
  • Don't imply uncertainty where we have definite assumptions (e.g., "we assume a 5% fall" rather than "it will probably fall 5%")
  • Individual choices have up to 4 trajectories which can be combined to make a pathway
  • Do not make predictions. Describe assumptions and possible implications.
  • Be careful with explanations of the form A or (B and C). These occur in biofuel relationship sections


  • Colours should be consistent across charts.
  • Captions should be left aligned (a.k.a. ragged right)
  • Charts that are repeated across pages should have the same scale (e.g., it should be possible to visually compare stacked energy charts for different sectors)
  • Use line markers: e.g., for line charts place x line markers at 5 year intervals


  • Individual pixels should not be visible. Use vector graphics where possible. All lines and text should be absolutely crisp and sharp when printed, not fuzzy.
  • The aspect ratio should not be distorted
  • Captions should be left aligned (a.k.a. ragged right)
  • The caption should indicate who owns the copyright, unless it is copyright DECC
  • The caption should explain the scale of the objects in the picture
  • Pictures of UK examples are preferred, examples from similar European country are ok.
  • Pictures that show an object in context, with scale marked, are preferred. For example, picture large area of solar panels on a roof, with 2, 3 and 4m2 marked out, rather than fake pictures of a single solar panel, scaled)


  • Call them a map, not a picture
  • Make sure the aspect ratio is right
  • If marking an area on a map, make sure it is a map projection that doesn't distort area too much
  • If a map only shows the implication of a single level, state what level in the caption
  • Explain the size of any relevant feature if it isn't marked on the chart (e.g., state the area of a box marking the potential sea area of wind turbines)


  • In caption explain any other relevant settings (e.g., for heating choice stack, explain heating demand choice assumed)
  • Make sure these are the same scale across pages (so at a glance you can see whether this one page note refers to a significant, or a trivial, sector.)