How to Grade/Sequence Tasks in TBLT?

Grading in TBLT
In TBLT, grading of tasks means sequencing or arranging them in a particular order according to a well defined rationale. Grading is a tool used in all syllabi to sequence materials for learning. In grammar-based syllabi, grammatical items are sequenced. In task-based syllabus, tasks are sequenced according to their difficulty so that learning happens on a smooth curve.

The techniques used in grammatical approaches to sequence tasks is not well received by the current task-based scholarship since all such approaches could do is provide a sequence of grammatical items and texts. This set of items or texts could reflect language abilities, but taken as individual items, they do not make any sense in terms of language ability/learning. Therefore, such an approach is rejected as being not very useful.

Tasks which are part of a task-based syllabus on the other hand do not claim that any one task reflects abilities to perform any other or all other tasks. Learning to perform a task enables you to do that particular task only (though you may be able to do many more tasks of the similar nature). Also, tasks are generally selected based on learners' needs. Therefore they do not come from any generalized assumption that some tasks form architypes or basis task types. Because of these reasons, unlike grammar-based syllabi, task-based syllabi do not seem to impede learning, but promote it in an organic fashion.

Grading Tools
Valency is the ability of a task to afford learning of particular item(s).
Criticality is the importance (or unavoidable significance) of an item to learn the target task.
Frequency is the importance of an item based on its number of occurrences in the real-world scenario.
Learnability is what the learners are capable of processing.
Task Complexity is judged based on multiple elements like amount of background knowledge available and to be used, language required to complete the task at hand, elements in a task, people involved in the task, planning time, etc. These are generally divided into cognitive factors and interactive factors.

• Cognitive factors are the factors that make demands on the attentional resources of the learner. Examples: the type of reasoning required, number of elements involved, whether information required is 'here-and-now' or not, planning time, task structure, number of steps in the task, etc. 
• Interactive factors are about interactional demands like open/closed task, one/two way information flow, number of participants, amount of contribution/negotiation needed, proficiency level, gender, age, power status, shared background and familiarity of interlocutors, etc. 

Task-based syllabi use relative complexity of tasks for task sequencing- not linguistic complexity. This is how task-based language syllabi are different from traditional grammatical syllabi.

Reference:
Long, M. (2014). Second Language Acquisition and Task-Based Language Teaching. Wiley Blackwell. Chichester.

Pedagogic Tasks: Selection and Simplification

Pedagogic Tasks
In task based language teaching, tasks need to be selected according to some reasonable logic. As per definitions of Willis and Willis (2007), any real-life task can be used in the classroom to teach language. Such tasks used in the classroom to teach language are called 'Pedagogic Tasks'.

How are Pedagogic Tasks selected?
Long (2014, p.234) proposes a step by step procedure to design a syllabus based on the principles of Task-based Language Teaching (TBLT). As per this procedure, a Needs Analysis sets of this process. Once the linguistic needs the learner has to perform in the real-world are identified, Target Tasks are defined. Target tasks are the tasks the learner has to perform in the real-world. Then these target tasks are classified at a more abstract level to as target task types, so that they form a kind of generic task-types to be used in classroom. This is important as the learners within classrooms may not always be homogeneous in their needs and/or abilities. It is after this stage, that Pedagogic Tasks are derived. Pedagogic tasks are simpler versions or parts of the larger target tasks. Gradually the complexity of pedagogic tasks are increased. In the final stage, the pedagogic task complexity will reach he level of complexity of target tasks.

How Pedagogic Tasks are Simplified
Pedagogic tasks are simplified versions of target tasks. They can be simplified using multiple ways. One is by limiting the content/language required for task completion. For example, if the target task is 'making online reservations', one can start with a simpler task of 'filling personal details in a form'. Another way is to divide the target task into many sub-tasks and doing them one by one. The final task or the 'exit task' in the module must be the most complex task, or a task that is on par with the target task in terms of task complexity.

References
Long, M. (2014). Second Language Acquisition and Task-Based Language Teaching. Wiley Blackwell. Chichester.
Willis, D. & Willis, J., (2007). Doing Task Based Teaching. Oxford University Press. Oxford