This work assess the accuracy of standard profile beam symmetry metrics used in radiotherapy quality assurance and compare them to the proposed correlative symmetric index metric and Structural similarity index. The objective is to propose a new method based on cross correlation, named correlative symmetric index, that we show is less susceptible to noise than traditional methods. In addition, a supplemental method called Structural Similarity Index is presented.Simulations of non symmetric beams with similar left and right areas were used to compare the effectiveness of quantifying beam symmetry through proposed and standard methods. To assess each metric dependence on noise, an assessment was performed on all metrics using a noisy, simulated, non symmetric beam profile. A comparison of standard and proposed methods was also performed to characterize beam symmetry of roughly symmetric beam profiles measures at different depths in a water tank.In quantifying beam symmetry, the proposed correlative index metric and Structural Similarity Index method resulted in values 0.387, 0.5401, respectively for the non symmetric noisy scenario. More traditional approaches of PDQ and area based symmetry resulted in values of 0.312 and 0.400, respectively, for the non symmetric noisy scenario. The corresponding percentage change between the non symmetric no noise and the non symmetric with noise for the Point Difference Quotient, area based symmetric value, Structural Similarity Index Measurement, and Correlative symmetric index were 0.111, 0.056, 0.1625, 0.008, respectively. For the clinical measured symmetric profiles all methods achieved values above 0.9. Comparisons of quantitative and qualitative metrics demonstrate that the proposed correlative symmetry index method outperforms both the pointwise and area based symmetric metrics for when beam profiles are noisy.