timeseries-financelisted

# Time series for finance Financial time series carry traps that general charting advice does not cover: periods are discrete and closed, values get restated, definitions change mid-series, and the thing people want to compare usually has a different magnitude than the thing beside it. --- ## Discrete periods are not continuous Monthly data is monthly. A line smoothed through monthly points invents intermediate values that never existed, and a reader will read them off. - **Columns for discrete periods** where each period is a closed fact — monthly revenue, quarterly bookings. - **Lines for continuously-varying quantities** sampled over time — cash balance, headcount, open AR. - **Never spline/smooth** between periods. Straight segments, or columns. - **Break the line at missing periods.** `chartkit.linePath` does this by default, deliberately — connecting across a gap draws data you do not have. - Mark **partial periods** (month-to-date) distinctly. An incomplete month plotted alongside complete ones reads as a collapse. --- ## Instead of dual axes Dual axes create a crossover point that is an artifact of two arbitrary scales, and readers infer meaning from it. Three honest substitutes: **1. Index both to 100** at a common base period. Now they share a scale and the comparison is real. ``` index_t = 100 × value_t / value_base ``` Best for comparing growth rates of differently-sized things. Label the base period in the axis title — an index chart with no stat