Here are the Paper 1 Written Production Criteria organised by bullet-point, in order to make the range of values as clear as possible. Note that:

• the key operative descriptive terms are in red
• I have added comments on the application of each set of descriptors, in blue

HL and SL distinctions - In Criterion A Language, there is mainly a 'one-step' difference between HL and SL - for example, under 'Grammar range', the wording of the SL 10-12 mark-band is the same as the HL 7-9 mark-band. In Criteria B Message and Criterion C Conceptual understanding, there is no 'step' - the wording of the mark-bands is the same at both levels. However, there will presumably be distinctions between the levels in (a) the level of difficulty of the tasks set, and (b) how the descriptors are interpreted and applied. These distinctions will only emerge from the first live exam session onwards.

Criterion A: Language  (/12)

SL & HL  (as indicated)

Headline: Command of the language 

(Wording the same for all mark-bands at both levels)

• Command of the language is limited.
• Command of the language is partially effective.
• Command of the language is effective and mostly accurate.
• Command of the language is mostly accurate and very effective.

The most significant word here is "effective", and I think we can take this to mean 'effective communication' - in other words, how well does one understand what meaning is intended?

But perhaps the meaning of 'well' changes as one moves up the levels of performance? Thus...

• at the lower end of the scale, 'effective' depends on how easily one can work out what meaning is intended, or how much of an 'effort of translation' one has to make
• at the upper end of the scale, 'effective' depends on how rich or complex or subtle is the meaning conveyed - are there nuances or implications or irony, for example?

Vocabulary

• Vocabulary is sometimes appropriate to the task. (SL 1-3 + HL 1-3)
• Vocabulary is appropriate to the task. (SL 4-6)  Vocabulary is generally appropriate to the task and varied. (HL 4-6)
• Vocabulary is appropriate to the task and varied. (SL 7-9)  Vocabulary is appropriate to the task and varied, including the use of idiomatic expressions. (SL 10-12 + HL 7-9)
• Vocabulary is appropriate to the task and nuanced and varied in a manner that enhances the message, including the purposeful use of idiomatic expressions. (HL 10-12)

Or, to present this in table-format :-

Grammar range

• Basic grammatical structures are used.  (SL 1-3)
• Some basic grammatical structures are used with some attempts to use more complex structures. (SL 4-6 + HL 1-3)
• A variety of basic and (some HL) more complex grammatical structures is used.  (SL 7-9 + HL 4-6)
• A variety of basic and more complex grammatical structures is used effectively.  (SL 10-12 + HL 7-9)
• A variety of basic and more complex grammatical structures is used selectively in order to enhance communication.  (HL 10-12)

Or, to present this in table-format :-

There are two factors here - the basic/complex continuum; and the 'used' continuum (i.e. from "attempts" to "selectively")

• basic/complex - but which sorts of grammar structure do we place where in this continuum?
• 'used' - the emphasis here is on "how skilfully or competently are different types of grammar used?"

Accuracy/errors  

(Wording the same for all mark-bands at both levels)

• Language contains errors in basic structures. Errors interfere with communication.
• Language is mostly accurate for basic structures but errors occur in more complex structures. Errors at times interfere with communication.
• Language is mostly accurate. Occasional errors in basic and in complex grammatical structures do not interfere with communication
• Language is mostly accurate. Minor errors in more complex grammatical structures do not interfere with communication.

Two interpretations are significant here:

• There is an assumption here that learning a language proceeds in a methodical sequence from 'basic' to 'complex', and that errors are neatly eliminated in that progression. This is observably not always so - some learners may handle complex structures well, but still display errors in poorly-grasped basics. Accordingly, one may sometimes have to negotiate between mark-bands and come to a compromise mark.
• The term 'interfere with communication' is important, and the sequence here is fairly clear. Privately, I would add, the qualifier 'significantly' to the 7-9 mark-band - as in 'do not interfere significantly'

Criterion B: Message  (/12)

SL & HL (Wording the same for all mark-bands at both levels)

Fulfillment of task

• The task is partially fulfilled.
• The task is generally fulfilled.
• The task is fulfilled.
• The task is fulfilled effectively.

In the final IB assessment, the 'task' will be defined in the Marking Notes, specifying the 'action verbs' (i.e. what the student has to do), and 'expected content' (i.e. how ideas should be developed and supported). All of these elements are then the indicators to study when judging to what extent the task has been 'fulfilled'.

Relevance

• Few ideas are relevant to the task.
• Some ideas are relevant to the task.
• Most ideas are relevant to the task.
• Ideas are relevant to the task.

The notion of 'relevance' can also be considered as 'focus' - the extent to which the message(s) of the text concentrate effectively on the evident, required purpose. To put it another way, how much of the text is poorly linked to the purpose of the text, or not at all?

Development of ideas

• Ideas are stated, but with no development.
• Ideas are outlined, but are not fully developed.
• Ideas are developed well, with some detail and examples.
• Ideas are fully developed, providing details and relevant examples.

The notion of 'development' involves looking for evidence that the student has thought through the ideas in detail. This implies a continuum from 'very simple basic statement' to 'all consequences and implications, with through and methodical support'.

Presentation & structure

• Ideas are not clearly presented and do not follow a logical structure, making the message difficult to determine.
• Ideas are generally clearly presented and the response is generally structured in a logical manner, leading to a mostly successful delivery of the message.
• Ideas are clearly presented and the response is structured in a logical manner, supporting the delivery of the message.
• Ideas are clearly presented and the response is structured in a logical and coherent manner that supports the delivery of the message.

It is important to make an analytical distinction between what ideas can be summarised from the text overall, and how those ideas have been organised so that the reader can follow a clear logical sequence of ideas easily and accurately. To put it another way, this is the distinction between what is explained and how it is explained.

Criterion C: Conceptual understanding   (/6)

SL & HL (Wording the same for all mark-bands at both levels)

Demonstration of Conceptual understanding

• Conceptual awareness is limited.
• Conceptual awareness is mostly demonstrated.
• Conceptual awareness is fully demonstrated.

Choice of text type

• The choice of text type is generally inappropriate to the context, audience or purpose.
• The choice of text type is generally appropriate to the context, audience and purpose.
• The choice of text type is appropriate to the context, purpose and audience.

How will ‘choice’ be tested? It would appear that the optional text types provided for each question/task may all be 'appropriate' in general terms - the judgement of 'appropriate' will be how skilfully the student makes use of the conventions of the chosen text type in order to fulfill the task and express his or her individual take on the subject.

Register & tone

• The register and tone are inappropriate to the context, purpose and audience of the task.
• The register and tone, while occasionally appropriate to the context, purpose and audience of the task, fluctuate throughout the response.
• The register and tone are appropriate to the context, purpose and audience of the task.

This may be seen as amplifying the 'Choice of text type' bullet point, above. For instance, if a student chooses an e-mail to a friend about a personal issue, and then deploys a formal register and an impersonal tone, this would be inappropriate to both text type and task.

Conventions

• The response incorporates limited recognizable conventions of the chosen text type.
• The response incorporates some conventions of the chosen text type.
• The response fully incorporates the conventions of the chosen text type.

This bullet point essentially involves identifying and counting commonly-accepted conventions for the chosen text type - the more, the better.