IBGE will update seasonal adjustment model of the Monthly Trade Survey

The Brazilian Institute of Geography and Statistics (IBGE) informed that it will update the parameters of the seasonal adjustment model of the Monthly Trade Survey (PMC) as early as the release of April 13, with data for February 2022.

“Updating seasonal adjustment models (parameters and adjustment factors) incorporates the most recent periods with available survey data. Due to the use of new seasonal adjustment models and estimation methods, seasonally adjusted series may have their values ​​revised from the beginning of the historical series to the most recent data — this will occur for all series whose new seasonal adjustment model differs from the one previously used”, warned the IBGE, in a technical note.

According to Cristiano Santos, PMC manager at IBGE, the update is a “standard procedure”, last carried out in April 2018.

Santos was unable to say whether the change will be able to dampen the strong revisions in the seasonally adjusted series that have occurred in recent months, especially under the impact of changes in consumption patterns caused by the Covid-19 pandemic.

However, he recalled that the new model will assimilate information collected during the health crisis, therefore, any changes in the seasonal pattern of consumer behavior.

“I don’t know if the adjustments tend to decrease (revisions in the seasonally adjusted series). With this update, the template helps to make more current adjustments. In this sense, the models are better, because they have more up-to-date data to make comparisons,” said Santos. “From the perspective of recent years, it (the updated seasonal adjustment model) incorporates this pandemic period, from 2020 onwards,” he added.

The change in the seasonal adjustment model was detailed by the agency in two technical notes published this Thursday, 10, on its website.