In contrast to File 1, File 2 is from a non-ideal supercapacitor which does not display a linear GCD profile, with the discharge slope varying with voltage (Figure ; File 2). 11 out of 14 groups analysed this dataset using Equation . This gave a larger variation in results compared to File 1 as the non-linear shape of the GCD amplified differences in analysis, including the voltage range used to determine the discharge slope and whether the Ohmic voltage drop was excluded from the calculation. As with File 1, two groups used incorrect equations to calculate the total capacitance. To attempt to account for the non-linearity of the data, Groups 3 and 12 used approaches which correspond to calculating the discharge energy via integration, and then calculating the capacitance from this (SI Section 3). While Group 12 converted the calculated discharge energy into a capacitance by equating to the energy stored in an ideal supercapacitor, the same approach they used for File 1, Group 3 equated to the energy stored in an ideal battery due to the non-linear nature of the discharge curve. This resulted in a lower reported capacitance value of 0.012 F (highlighted in Figure in blue; SI Section 3).