What do sentence recall tests measure?

In sentence recall tests, the child listens to one sentence and tries to repeat it as precisely as he can.  Usually, the sentence's length and complexity grow as the test progresses.

This test is usually thought of as measuring memory span.  Memory span, in CHC theory, is a narrow ability within short term memory.  Memory span is "the ability to encode information, keep it in immediate awareness and produce it immediately in the order in which it was presented."  Or, put another way: "the ability to attend to and immediately recall temporally ordered elements in the correct order after a single presentation."  (Flanagan et al.,2007, Schneider and McGrew, 2012 ). 

Sentence recall is also an efficient marker of SLI – Specific Language Impairment and of dyslexia.  Performance in sentence recall tests is also related to reading comprehension.

A few researchers, including Baddeley, suggest that the sentence recall task involves short term memory as well as long term memory.  Sentence recall requires using general information, semantic knowledge (that help us understand what the sentence is about - the 'gist' of the sentence), and grammatical and syntactic knowledge.  Utilizing these knowledge types requires the involvement of long term memory.   The sentence recall task also requires keeping track of the structural aspects of the sentence ("keeping" the word order in the phonological loop, for example).  This involves short term memory.

Gathercole found in 2005, that people with high phonological memory are able to retain the word order in sentences much better than people with low phonological memory.  People with low phonological memory have more errors of omissions  and insertions  (they add and/or delete words from the sentence).  Sentence recall tests are correlated with nonword repetition tests, which are influenced by memory span.

Marshall and Nation found in 2003, that children with normal levels of reading accuracy and speed but low reading comprehension, also have low sentence recall.  These children have no difficulties in memory span tests.  The researchers suggest that the low performance in sentence recall tests is related to long term memory's involvement in sentence recall tasks.

In this study:

The role of sentence recall in reading and language skills of children with learning difficulties.  Alloway, T.P. and Gathercole, S.E.  learning and Individual differences, 15 (2005) 271-282

http://www.academia.edu/2651151/The_role_of_sentence_recall_in_reading_and_language_skills_of_children_with_learning_difficulties

participated children in elementary school with learning difficulties.  They were tested with reading, language, working memory, expressive vocabulary and sentence recall tests and the Wechsler test.  The hardest items in the sentence recall test were not longer sentences but were more complex sentences.  The goal was to see whether the sentence recall test is related to reading or to language skills.

A correlation of 0.6 was found between sentence recall and memory span.  But, when the unique contribution of each factor to the prediction of reading and language skills was examined, it was found that sentence recall explained a significant amount of the variance in reading and language skills above the contribution of age, IQ, expressive vocabulary, memory span and working memory.

So, sentence recall test measures much more than memory span.  Gathercole and Alloway suggest that sentence recall predicted performance in reading and   language tests because    sentence recall tests requires the use of both short term memory and linguistic and conceptual knowledge found in long term memory.