# Does noise model in qiskit impact the optimized parameters for QAOA?

I have read this paper about the effects of quantum noise on QAOA.

In the conclusion, it says: QAOA is a noise-tolerant algorithm, quantum noise does not change the QAOA quantum circuit parameter optimization direction, for both noisy and ideal QAOA cost functions, the optimized QAOA parameters being nearly the same.

I use qiskit to perform some experiments. Basically, I add a noise model to the simulator during the parameter training process. I found that, the optimized parameters are different when I use qasm_simulator and COBYLA. However, when I use statevector_simulator and no matter which optimizer, the optimized parameters are exactly the same with and without noise model.

I know that for statevector_simulator, there is no sampling noise. Is the difference of the optimized parameters caused by the sampling noise for qasm_simulator? Will the noise model impact the value of the optimized parameters theoretically?