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The Trilemma Between Accuracy, Timeliness and Smoothness in Real-Time Signal Extraction

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The evaluation of economic data and monitoring of the economy is often concerned with an assessment of mid-and long-term dynamics of time series (trend and/or cycle). Frequently, one is interested in the most recent estimate of a target signal, a so-called real-time estimate. Unfortunately, real-time signal extraction is a difficult prospective estimation problem which involves linear combinations of one-and possibly infinitely many multi-step ahead forecasts of a series. We here address performances of real-time designs by proposing a generic Direct Filter Approach (DFA). We decompose the ordinary MSE into Accuracy, Timeliness and Smoothness error components, and we propose a new two-dimensional tradeoff between these conflicting terms, the so-called ATS-trilemma. With this formalism, we are able to derive a general class of optimization criteria that allow the user to address specific research priorities, in terms of the Accuracy, Timeliness and Smoothness properties of the resulting real-time filter.
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... Based on this contrast, we may infer that MBA is likely to outperform DFA if the transformed series is subject to a permanent and slowly varying level-shift; preferences for either filter design may be adopted, depending on whether log-returns of the data are deemed to follow such a non-stationary pattern 8. A comprehensive treatment of frequency-domain characteristics is provided in Wildi and McElroy (2014), where the authors derive a generic optimization criterion addressing noise-suppression, timeliness, and accuracy of real-time designs. for understanding the U.S. economy-both retail and housing are key facets of consumption and production activity in advanced economies. ...
... Our treatment is illustrated through two main examples: trend estimation from a retail series, and seasonal adjustment of a construction series. Other work-the subject of the companion paper Wildi and McElroy (2014) further explores the design of filters, taking into account their frequency domain properties (described via the gain and phase delay functions) directly in the DFA criterion. ...
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... Another possible extension is motivated by Wildi and McElroy (2019) , which develops a still more general error criterion allowing for customization of filters -so that a practitioner can directly accomodate specific user-priorities of having a smoother real-time estimate of the signal, versus having a more timely estimate (i.e., less phase delay). ...
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