The presence of adventitious carbon on samples analysed by X‐ray photoelectron spectroscopy can complicate data interpretation. Because adventitious carbon can contain a significant amount of oxygen‐containing functional groups, accounting for its contribution is essential when analysing oxygen. For example, accurately determining the oxygen concentration—free from adventitious carbon contributions—is often crucial for some data interpretation. Additionally, when modelling high‐resolution oxygen 1s spectra, the organic oxygen must be considered to ensure accurate interpretation. Although these aspects of data interpretation should ideally be guided by stoichiometry, the process can be tedious and challenging, particularly for novice users. This Insight Note introduces a method for accounting for organic oxygen associated with adventitious carbon. It provides background information, outlines key assumptions and includes an easy‐to‐use Excel calculator to support this analysis, making the approach more accessible, especially for novice users.

X‐ray photoelectron spectroscopy (XPS) is widely employed across various research fields due to its surface and chemical sensitivity. However, accurate interpretation poses a challenge due to the lack of comprehensive reference data in the literature, leading to misinterpretation, especially among novice users. Analyzing the chemical state of indium and indium‐containing compounds is particularly challenging due to subtle shifts in the binding energies of the commonly used 3d core line. This paper presents and discusses a collection of reference data, including the In 3d, In 3p, In 4d, In MNN, and relevant counter ion signals. Additionally, it explores other useful information such as the modified Auger parameter and Wagner (or chemical state) plots. The utility of X‐ray–induced Auger electrons is demonstrated in the speciation of mixed systems.