In this blog post graphic methods are used to describe Serbian monthly household savings time series.
Two types of a line graph could be used to show changes in monthly household savings over time. The first displays both time series on a single graph. The second type of graph displays each series on a separate panel. On such graphs any persistent pattern related to trend or seasonal factors should be clearly visible.
Figure 1 shows line graphs of monthly household savings time series on the same panel grouped by currency (dinar and foreign).
The dinar and FX-indexed savings series in short-term shows rapidly increasing trend with a lot of variation around such trend. The dinar and FX-indexed savings series in long-term is also characterised by a positive trend, but not at the same growth rate as the savings in short-term. We could make the same observations about the both foreign currency savings time series.
Second, the both dinar and foreign currency savings in short-term dominate the total household savings with bank in Serbia. For instance, in 2019 dinar savings in short-term is almost 7 times greater than the dinar savings in long-term. At the same time foreign currency savings in short-term is about 4 times greater than savings in long-term.
Third, from these graphs it looks like that in some periods there is a movement in opposite direction between short-term and long-term savings in case of both dinar and foreign currency savings. For instance, in period 2015-2017 there is a negative trend in foreign currency savings in short-term, up until 2016, and a positive trend afterward. In the same period foreign currency savings in long-term moved in opposite direction, i.e. we have an increase until 2016 and decrease afterward. Such observations about synchronous movement of short-term and long-term series could be used when modelling them. Instead of forecasting values of each individual time series we can use, for example, hierarchical time series approach to improve our forecast.
Figure 2 shows line graphs of monthly household savings time series on the same panel grouped by term (short and long).
Obviously both foreign currency savings in short- and long-term dominate dinar savings. For instance, in the first two months in 2019 foreign currency savings was about 80+ times greater in short-term and 20+ times greater in long-term when comparing foreign currency savings to dinar savings.
Figure 3 shows line graphs of monthly household savings time series on the separate panels. It does not look like that there is a significant seasonal component in any of these four household savings time series.