Sound intensity level and sound pressure level are roughly equivalent

Evidence

Loudness is mainly the perceptual correlate of sound intensity, which is usually expressed in dB SPL as sound pressure level on a logarithmic scale. However, loudness judgments are also affected by several other variables, including physical sound parameters like e.g. duration, spectral content and temporal modulation as well many more acoustic and non-acoustic factors, including the particular task or context and personal factors like the individual hearing status (Florentine et al. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2610 (#contradicts, via linked claim)

Intensity, while it has concrete bearing on what sound will do to the hearing apparatus, is not the same metric as perceived loudness, which doubles with every ten-decibel increase, so that going from 40 to 50 decibels equals a rise of 100 percent. — George Michelsen Foy, Zero Decibels, 53 (#qualifies, via linked claim)

Categorization

• XREF: connects to: Sound pressure amplitude falls off as the inverse of distance from a source; Sound intensity measures power density as watts per unit area — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 301; Sound level references implicitly mean sound pressure level (+3 more)

Broader Connections

• Loudness depends on more than physical sound intensity alone #contradicts (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2610
• Hearing integrates sound intensity over a fixed 200 ms window #complicates (0.72)
• Perceived loudness and physical sound intensity follow different, non-intuitive mathematical scales #qualifies (0.72) — George Michelsen Foy, Zero Decibels, 53