The series name matters more than the line color
First establish the object: security price, index, full position value or return measure. Then check currency, source, dates and units. A bond’s clean price and the amount including accrued coupon are not the same series; a share price and a result including dividends answer different questions. The SEC separately emphasizes accounting for distributions and calculation methodology.[12](#source-market-performance) If a percentage appears nearby, determine its basis: change from the beginning of the period, annual figure or share of another value. “Growth” without a base is not enough information for comparison.
Also check which price was used: last trade, calculated value, closing price or a market-side quote. If a series consists of infrequent trades, a smooth line between them does not prove calm continuous movement. The connecting segment is a drawing method, not evidence of trading at every moment. Missing observations and data pauses need explicit marking. Counterexample: there were no records between observations, but software connected the points. The reader saw a path absent from the source data. Ask for the observation table, not only the image.
Scale changes visual impression
A linear vertical scale gives equal distance to equal monetary changes. A logarithmic scale links distance to equal relative changes; the choice should be stated. A truncated vertical axis can visually enlarge a small movement. Changing the time-window width also changes the impression: the same episode can look like a sharp jump or a small part of a long series. These are presentation features, not business properties. Check claims such as “barely changed” or “rose rapidly” against numbers and scale, not the slope on screen.
Educational hypothetical example: price changes from 100 to 80 roubles. The fall is (80 / 100 − 1) × 100 = −20%. A return from 80 to 100 is (100 / 80 − 1) × 100 = 25%. The same 20-rouble change does not mean the same percentage because the denominator differs. After a fall, one cannot add the same percentage and automatically expect recovery of the original amount. The example explains base asymmetry, not a forecast for any instrument. Costs and payments are deliberately excluded.
A candle aggregates but does not preserve the whole path
For an educational display, take a candle with four values: open, high, low and close of a chosen interval. The body connects open and close; additional lines show the range boundaries. The color rule depends on the interface and should be labeled. These four values do not reveal the order in which high and low were reached or how many trades occurred at each level. The same four numbers can arise from different intraperiod sequences. A candle shape is therefore not proof of one history of participant behavior or of the next price direction.
The aggregation interval affects detail. Combining observations hides some changes, while a smaller interval makes them visible. Read volume with its units: number of securities, contracts and monetary turnover are not interchangeable. A moving average is a transformation of the series, not new independent facts. Educational example: the average of 100, 110 and 90 is 100. It smooths fluctuations, but the fall to 90 has not disappeared. The averaging parameter determines which past information receives weight; the line itself adds no knowledge of the future.
Adjustments and period selection
A series may be adjusted for corporate events or distributions to make comparison possible. Establish what is adjusted and whether the original price can be reconstructed. The SEC treats methodology and selection of convenient periods as material questions in evaluating presented performance.[12](#source-market-performance) Starting after a major fall and ending before a new fall can create a selectively favorable history. Counterexample: the chart is accurately built from data, but the period hides less successful stages. Technical correctness of the image does not equal honest conclusions from it.
Access to data is not a right to redistribute it
Educational literacy does not require copying an exchange feed or publishing someone else’s historical database. MOEX information-product terms separately restrict ways of using and redistributing data.[14](#source-market-data-rights) Being able to view a page does not mean having a license to redistribute the series; particular rights must be checked separately. Examples on this portal are independent and hypothetical, without real quotes or external images. Before drawing a conclusion, check object, units, period, scale, missing values, adjustments and costs. Even a fully checked image explains past data presentation, but does not guarantee a forecast or justify a personal trading decision.
Tick axis: an event instead of an equal minute
In a tick representation, one mark may correspond to one registered trade, and one bar to a specified number of trades. For example, Sierra Chart documentation defines a tick in Number of Trades Per Bar mode as a trade and requires individual-trade source data.[5](#source-mk-sierra-ticks) It is not the minimum price step and not necessarily a quote change: the term depends on the provider.
For the price sequence 100, 101, 100, 102, 103, 102, bars of three trades have OHLC respectively (100, 101, 100, 100) and (102, 103, 102, 102). The horizontal axis of an even event chart is trade or group order; the vertical axis is price. The first three trades could occur in one second and the next three in one hour: equal bar width does not mean equal calendar time. Individual timestamps preserve that difference but do not turn an event scale into a minute scale.
Trade size is also lost: three trades of one security and three trades of one thousand give the same number of ticks under the selected convention. Filtering, provider aggregation and missing records change bars. Without a volume table, a tick chart cannot reconstruct monetary turnover, calendar-time speed or guaranteed execution at observed prices.
Histogram: define both axes first
For a statistical histogram, NIST places intervals of the measured variable on the horizontal axis and the number of observations in them on the vertical axis; normalization choices change the meaning of height.[4](#source-mk-nist-histogram) Take the author’s price changes −2, −1, −1, 0, 1, 3. For intervals [−2;0), [0;2), [2;4], frequencies are 3, 2, 1 and shares are 1/2, 1/3, 1/6. This is a distribution of six observations, not a sequence of six days and not a probability of the next result.
Columns labeled “day — volume” have a different horizontal axis: calendar time, not price-change intervals. A panel showing the difference between two indicator lines may show negative columns around zero; its Y-axis is in units of that difference, not number of trades. Calling all three drawings simply a histogram is insufficient. With unequal statistical-bin widths, density height equals frequency divided by observation count and width; compare areas, not bare heights. Moving bin boundaries changes the distribution’s appearance but creates no new data or trading signal.