A method performed by a fabrication system, the method comprising: receiving a design of an integrated computational element, the ICE design comprising specification of a substrate and a plurality of layers, their respective target thicknesses and complex refractive indices, wherein complex refractive indices of adjacent layers are different from each other, and wherein a notional ICE fabricated in accordance with the ICE design is related to a characteristic of a sample, and identification of one or more critical layers from among the plurality of layers, wherein a layer of the ICE is identified as a critical layer if potential variations of its thickness or complex refractive index due to expected variations of the fabrication cause degradation of the ICE's performance that exceeds a threshold degradation, otherwise the layer of the ICE is identified as a non-critical layer; and forming the layers of the ICE, wherein at least one critical layer of the ICE is formed using two or more forming steps to form respective two or more sub-layers of the critical layer, and at least one non-critical layer of the ICE is formed using a single forming step. receiving a design of an integrated computational element, the ICE design comprising specification of a substrate and a plurality of layers, their respective target thicknesses and complex refractive indices, wherein complex refractive indices of adjacent layers are different from each other, and wherein a notional ICE fabricated in accordance with the ICE design is related to a characteristic of a sample, and identification of one or more critical layers from among the plurality of layers, wherein a layer of the ICE is identified as a critical layer if potential variations of its thickness or complex refractive index due to expected variations of the fabrication cause degradation of the ICE's performance that exceeds a threshold degradation, otherwise the layer of the ICE is identified as a non-critical layer; and specification of a substrate and a plurality of layers, their respective target thicknesses and complex refractive indices, wherein complex refractive indices of adjacent layers are different from each other, and wherein a notional ICE fabricated in accordance with the ICE design is related to a characteristic of a sample, and identification of one or more critical layers from among the plurality of layers, wherein a layer of the ICE is identified as a critical layer if potential variations of its thickness or complex refractive index due to expected variations of the fabrication cause degradation of the ICE's performance that exceeds a threshold degradation, otherwise the layer of the ICE is identified as a non-critical layer; and forming the layers of the ICE, wherein at least one critical layer of the ICE is formed using two or more forming steps to form respective two or more sub-layers of the critical layer, and at least one non-critical layer of the ICE is formed using a single forming step. at least one critical layer of the ICE is formed using two or more forming steps to form respective two or more sub-layers of the critical layer, and at least one non-critical layer of the ICE is formed using a single forming step.