Highly skilled musicians can sight-read silently; that is, they can look at the printed music and hear it in their heads without playing or singing; see Audiation. (True sight-reading or sight-singing—not code-deciphering—is actually notational audiation.) Less able sight-readers generally must at least hum or whistle in order to sight-read effectively. This distinction is analogous to ordinary prose reading during the early Middle Ages, when the ability to read silently was notable enough for St. Augustine to comment on it .
According to , "the ability to hear the notes on the page is clearly akin to music reading and should be considered a prerequisite for effective performance.... Egregious errors can occur when a student, analyzing a piece of music, makes no effort to play or hear the composition but mechanically processes the notes on the page."
Some musicians -- self-taught guitar players, in particular -- can take a popular song and transpose the music to fit their voice range, ease of playing the guitar chords, or any other reason. They don't even have to know how to read music -- just knowledge to play the transposed guitar chords is all it takes to take a song that is "too high," or "too low," and tailor-make it fit one's voice-range.
Storage of notational information in working memory can be expressed in terms of the amount of information (load) and the time for which it must be held before being played (latency). The relationship between load and latency changes according to tempo, such that t = x/y, where t is the change in tempo, x is the change in load, and y is the change in latency. Some teachers and researchers have proposed that the eye–hand span can be trained to be larger than it would otherwise be under normal conditions, leading to more robust sight-reading ability.
Sight-reading also depends on familiarity with the musical idiom being performed; this permits the reader to recognize and process frequently occurring patterns of notes as a single unit, rather than individual notes, thus achieving greater efficiency. This phenomenon, which also applies to the reading of language, is referred to as chunking. Errors in sight-reading tend to occur in places where the music contains unexpected or unusual sequences; these defeat the strategy of "reading by expectation" that sight-readers typically employ.
This emphasis on sight-reading, according to McNerney, prepares musicians for studio work "playing backing tracks for pop performers or recording [commercials]." The expense of the studio, musicians, and techs makes sight-reading skills essential. Typically, a studio performance is "rehearsed" only once to check for copying errors before recording the final track. Many professional big bands also sight-read every live performance. They are known as "rehearsal bands" though their performance is the rehearsal.
According to , score reading is an important skill for those interested in the conducting profession and "Conductors such as the late Robert Shaw and Yoel Levi have incredibly strong piano skills and can read at sight full orchestral scores at the piano." surveyed over 40 professional associations regarding opportunities and requirements in music careers. They found sight-reading, transposition, and improvisation among required skills for careers in instrumental performance including armed forces musician, orchestra musician, small ensemble musician, concert soloist, band musician, and clinician. Employment in music for worship including organist, choir director, cantor, and hazan require skills in sight-reading and open score reading. Sight-singing and memorization are required for vocal performers such as dance band or night club vocalist, concert or opera chorus member, concert soloist, and opera soloist.
Hardy reviewed research on piano sight-reading pedagogy and identified a number of specific skills essential to sight-reading proficiency:
Beauchamp (1999) identifies five building blocks in the development of piano sight-reading skills:
Grand-staff knowledge consists of fluency in both clefs such that reading a note evokes an automatic and immediate physical response to the appropriate position on the keyboard. Beauchamp asserts it is better to sense and know where the note is than what the note is. The performer doesn't have time to think of the note name and translate it to a position, and the non-scientific note name doesn't indicate the octave to be played. Beauchamp reports success using a Key/Note Visualizer, note-reading flashcards, and computer programs in group and individual practice to develop grand-staff fluency (see External links, below for example).
Udtaisuk also reports that a sense of keyboard geography and an ability to quickly and efficiently match notes to keyboard keys is important for sight-reading. He found that "computer programs and flash cards are effective ways to teach students to identify notes [and] enhance a sense of keyboard geography by highlighting the relationships between the keyboard and the printed notation (see External links, below for example)."
Most students don't sight-read well because it requires specific instruction, which is seldom given. A major challenge in sight-reading instruction, according to Hardy, is obtaining enough practice material. Since practicing rehearsed reading does not help improve sight-reading, a student can only use a practice piece once. Moreover, the material must be at just the right level of difficulty for each student, and a variety of styles is preferred. Hardy suggests music teachers cooperate to build a large lending library of music and purchase inexpensive music from garage sales and store sales.
Washington State has piloted a classroom based assessment which requires 5th and higher grade students to sight-sing from sheet music without the aid of instruments. It is suggested that students use solfege or numbering systems or fingering without instruments as aids. Sight-singing is a learning requirement in the state at the 8th grade level. Most students and adults cannot sight-sing, and many professional singers cannot sing by sight. However, in combination with an assessment which requires composing music on a staff as early as 5th grade, it is hoped that such a requirement will raise arts achievement. Pilot data show that many students can meet or exceed such standards. Other states are evaluating possible performance assessments as well.