Section 78(b) of the Evidence Act 1995 (NSW) does not require absolute necessity; the word 'necessary' connotes a higher hurdle than 'helpful' or 'convenient' but is subject to a purposive interpretation. Perceptions of the aftermath of an incident can properly be described as perceptions 'about' the event for the purposes of s 78(a), so that a witness who did not observe the event itself but observed its aftermath may give lay opinion evidence under s 78. A question mark preceding an opinion in a business record reduces but does not eliminate its probative force. Section 78 should not be constricted by importing common law requirements (such as evanescence or complication of facts) that do not appear in the statutory text.
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