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VIDBE-Q Volume 64 Issue 2
effectiveness of using CTD to teach students with visual impairments either
braille words or braille contractions. All studies were found to be effective.
How to Use Constant Time Delay
Constant time delay (CTD) is a systematic prompting procedure that
uses explicit teaching of sight words (or braille words/contractions) on
flashcards. A screening is used to get a list of unknown target words
(usually 15-20 words). The chosen list is then divided into word sets that
are taught separately (usually a targeted 3 or 4 word sets when teaching
brand new words or contractions). The person implementing the
intervention presents the flashcard and pairs it with the instructional cue
(i.e., "Read the word"). The instructional cue is followed by the model
prompt (i.e., "This word is dog"). First, there is a 0-second delay between
instructional cue and model prompt, which is when the actual teaching of
the word or contraction occurs. The "time delay" gets introduced in
subsequent sessions, when you are trying to have your student actually
read the word or contraction. The aforementioned studies typically used a
5-second delay, but you can choose a time delay that is most appropriate
for your student and his/her cognitive processing needs.
A great aspect of CTD is the simplistic nature of the intervention. It is
a quick intervention, usually lasting roughly between five and ten minutes,
