Maximum difference between pairs of models binned to the native resolving power of each JWST instrument, without instrumental noise. All models are for a planet with R_p = 1.5 ﹩{R}_{\oplus }﹩ and T = 400 K. The color scale is indicated for both a GJ 1214-type host star and a Sun-like star. All model #1's have a surface gravity of 9.3 m s⁻², and all model #2's have a surface gravity of 20.7 m s⁻². For reference, the suggested noise floors are ±20 ppm and ±50 ppm for NIRISS/NIRSpec and MIRI LRS, respectively.