No, they are not the same thing. A key difference is that a deductible reduces the limit of insurance but an SIR does not. If a policy includes a deductible and a loss exceeds the limit, the insurer will pay the limit of insurance minus the deductible. If a policy includes an SIR and a loss exceeds the limit, the insurer will pay the full limit of insurance once the insured has paid the SIR.