healthyverse_tsa

Time Series Analysis and Nested Modeling of the Healthyverse Packages

Steven P. Sanderson II, MPH - Date: 09 June, 2025

This analysis follows a Nested Modeltime Workflow.

Get Data

glimpse(downloads_tbl)
## Rows: 141,817
## Columns: 11
## $ date      <date> 2020-11-23, 2020-11-23, 2020-11-23, 2020-11-23, 2020-11-23,…
## $ time      <Period> 15H 36M 55S, 11H 26M 39S, 23H 34M 44S, 18H 39M 32S, 9H 0M…
## $ date_time <dttm> 2020-11-23 15:36:55, 2020-11-23 11:26:39, 2020-11-23 23:34:…
## $ size      <int> 4858294, 4858294, 4858301, 4858295, 361, 4863722, 4864794, 4…
## $ r_version <chr> NA, "4.0.3", "3.5.3", "3.5.2", NA, NA, NA, NA, NA, NA, NA, N…
## $ r_arch    <chr> NA, "x86_64", "x86_64", "x86_64", NA, NA, NA, NA, NA, NA, NA…
## $ r_os      <chr> NA, "mingw32", "mingw32", "linux-gnu", NA, NA, NA, NA, NA, N…
## $ package   <chr> "healthyR.data", "healthyR.data", "healthyR.data", "healthyR…
## $ version   <chr> "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0…
## $ country   <chr> "US", "US", "US", "GB", "US", "US", "DE", "HK", "JP", "US", …
## $ ip_id     <int> 2069, 2804, 78827, 27595, 90474, 90474, 42435, 74, 7655, 638…

The last day in the data set is 2025-06-07 23:26:08, the file was birthed on: 2024-08-07 07:35:44, and at report knit time is -7307.84 hours old. Happy analyzing!

Now that we have our data lets take a look at it using the skimr package.

skim(downloads_tbl)
   
Name downloads_tbl
Number of rows 141817
Number of columns 11
_______________________  
Column type frequency:  
character 6
Date 1
numeric 2
POSIXct 1
Timespan 1
________________________  
Group variables None

Data summary

Variable type: character

skim_variable n_missing complete_rate min max empty n_unique whitespace
r_version 102284 0.28 5 5 0 47 0
r_arch 102284 0.28 3 7 0 5 0
r_os 102284 0.28 7 15 0 22 0
package 0 1.00 7 13 0 8 0
version 0 1.00 5 17 0 60 0
country 12052 0.92 2 2 0 163 0

Variable type: Date

skim_variable n_missing complete_rate min max median n_unique
date 0 1 2020-11-23 2025-06-07 2023-06-30 1658

Variable type: numeric

skim_variable n_missing complete_rate mean sd p0 p25 p50 p75 p100 hist
size 0 1 1133393.91 1517075.59 355 14701 289703 2367728 5677952 ▇▁▂▁▁
ip_id 0 1 10432.09 18579.77 1 284 3039 11684 209747 ▇▁▁▁▁

Variable type: POSIXct

skim_variable n_missing complete_rate min max median n_unique
date_time 0 1 2020-11-23 09:00:41 2025-06-07 23:26:08 2023-06-30 19:38:29 86870

Variable type: Timespan

skim_variable n_missing complete_rate min max median n_unique
time 0 1 0 59 12H 6M 47S 60

We can see that the following columns are missing a lot of data and for us are most likely not useful anyways, so we will drop them c(r_version, r_arch, r_os)

Plots

Now lets take a look at a time-series plot of the total daily downloads by package. We will use a log scale and place a vertical line at each version release for each package.

Now lets take a look at some time series decomposition graphs.

Feature Engineering

Now that we have our basic data and a shot of what it looks like, let’s add some features to our data which can be very helpful in modeling. Lets start by making a tibble that is aggregated by the day and package, as we are going to be interested in forecasting the next 4 weeks or 28 days for each package. First lets get our base data.

## 
## Call:
## stats::lm(formula = .formula, data = df)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -146.72  -35.81  -11.05   26.84  814.94 
## 
## Coefficients:
##                                                      Estimate Std. Error
## (Intercept)                                        -1.538e+02  6.801e+01
## date                                                9.637e-03  3.603e-03
## lag(value, 1)                                       1.050e-01  2.433e-02
## lag(value, 7)                                       9.664e-02  2.521e-02
## lag(value, 14)                                      8.917e-02  2.520e-02
## lag(value, 21)                                      6.880e-02  2.527e-02
## lag(value, 28)                                      7.085e-02  2.517e-02
## lag(value, 35)                                      6.726e-02  2.526e-02
## lag(value, 42)                                      5.100e-02  2.540e-02
## lag(value, 49)                                      6.913e-02  2.526e-02
## month(date, label = TRUE).L                        -9.569e+00  5.106e+00
## month(date, label = TRUE).Q                         4.197e+00  5.114e+00
## month(date, label = TRUE).C                        -1.353e+01  5.128e+00
## month(date, label = TRUE)^4                        -7.450e+00  5.163e+00
## month(date, label = TRUE)^5                        -1.091e+01  5.113e+00
## month(date, label = TRUE)^6                        -3.169e+00  5.208e+00
## month(date, label = TRUE)^7                        -7.680e+00  5.090e+00
## month(date, label = TRUE)^8                        -3.635e+00  5.094e+00
## month(date, label = TRUE)^9                         6.147e+00  5.103e+00
## month(date, label = TRUE)^10                        3.124e+00  5.077e+00
## month(date, label = TRUE)^11                       -5.042e+00  5.189e+00
## fourier_vec(date, type = "sin", K = 1, period = 7) -1.148e+01  2.329e+00
## fourier_vec(date, type = "cos", K = 1, period = 7)  7.972e+00  2.449e+00
##                                                    t value Pr(>|t|)    
## (Intercept)                                         -2.262 0.023856 *  
## date                                                 2.675 0.007555 ** 
## lag(value, 1)                                        4.314 1.70e-05 ***
## lag(value, 7)                                        3.834 0.000131 ***
## lag(value, 14)                                       3.539 0.000413 ***
## lag(value, 21)                                       2.722 0.006551 ** 
## lag(value, 28)                                       2.815 0.004937 ** 
## lag(value, 35)                                       2.663 0.007826 ** 
## lag(value, 42)                                       2.008 0.044792 *  
## lag(value, 49)                                       2.736 0.006290 ** 
## month(date, label = TRUE).L                         -1.874 0.061091 .  
## month(date, label = TRUE).Q                          0.821 0.411978    
## month(date, label = TRUE).C                         -2.638 0.008420 ** 
## month(date, label = TRUE)^4                         -1.443 0.149221    
## month(date, label = TRUE)^5                         -2.134 0.032977 *  
## month(date, label = TRUE)^6                         -0.608 0.542959    
## month(date, label = TRUE)^7                         -1.509 0.131561    
## month(date, label = TRUE)^8                         -0.714 0.475617    
## month(date, label = TRUE)^9                          1.204 0.228581    
## month(date, label = TRUE)^10                         0.615 0.538348    
## month(date, label = TRUE)^11                        -0.972 0.331391    
## fourier_vec(date, type = "sin", K = 1, period = 7)  -4.928 9.17e-07 ***
## fourier_vec(date, type = "cos", K = 1, period = 7)   3.256 0.001154 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 58.68 on 1586 degrees of freedom
##   (49 observations deleted due to missingness)
## Multiple R-squared:  0.2394, Adjusted R-squared:  0.2288 
## F-statistic: 22.69 on 22 and 1586 DF,  p-value: < 2.2e-16

NNS Forecasting

This is something I have been wanting to try for a while. The NNS package is a great package for forecasting time series data.

NNS GitHub

library(NNS)

data_list <- base_data |>
    select(package, value) |>
    group_split(package)

data_list |>
    imap(
        \(x, idx) {
            obj <- x
            x <- obj |> pull(value) |> tail(7*52)
            train_set_size <- length(x) - 56
            pkg <- obj |> pluck(1) |> unique()
            sf <- NNS.seas(x, modulo = 7, plot = FALSE)$periods
            
            cat(paste0("Package: ", pkg, "\n"))
            NNS.ARMA.optim(
                variable = x,
                h = 28,
                training.set = train_set_size,
                #seasonal.factor = seq(12, 60, 7),
                seasonal.factor = sf,
                pred.int = 0.95,
                plot = TRUE
            )
            title(
                sub = paste0("\n",
                             "Package: ", pkg, " - NNS Optimization")
            )
        }
    )
## Package: healthyR
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.7430823524398"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21, 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.46052619688832"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21, 63, 91 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.36262847890346"
## [1] "BEST method = 'lin', seasonal.factor = c( 21, 63, 91 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 2.36262847890346"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 21, 63, 91 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.44580036577609"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 21, 63, 91 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.44580036577609"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 21, 63, 91 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.00473680136983"
## [1] "BEST method = 'both' PATH MEMBER = c( 21, 63, 91 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.00473680136983"

## Package: healthyR.ai
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.68227576034834"
## [1] "BEST method = 'lin', seasonal.factor = c( 63 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.68227576034834"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.05378278722203"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.05378278722203"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.74243003055983"
## [1] "BEST method = 'both' PATH MEMBER = c( 63 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.74243003055983"

## Package: healthyR.data
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.55411104733254"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 84 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.32252538886903"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 84, 91 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.22588949750934"
## [1] "BEST method = 'lin', seasonal.factor = c( 63, 84, 91 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 2.22588949750934"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63, 84, 91 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 2.31469558509605"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63, 84, 91 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 2.31469558509605"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63, 84, 91 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 2.12231407694237"
## [1] "BEST method = 'both' PATH MEMBER = c( 63, 84, 91 )"
## [1] "BEST both OBJECTIVE FUNCTION = 2.12231407694237"

## Package: healthyR.ts
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.16511889505517"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21, 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.8181038950464"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 21, 56, 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.69743722439823"
## [1] "BEST method = 'lin', seasonal.factor = c( 21, 56, 63 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 2.69743722439823"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 21, 56, 63 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 5.17111413785284"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 21, 56, 63 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 5.17111413785284"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 21, 56, 63 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.16246033198328"
## [1] "BEST method = 'both' PATH MEMBER = c( 21, 56, 63 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.16246033198328"

## Package: healthyverse
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 28 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 4.19172370298605"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 28, 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 4.01373480488995"
## [1] "BEST method = 'lin', seasonal.factor = c( 28, 56 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 4.01373480488995"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 28, 56 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.83478312995496"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 28, 56 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.83478312995496"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 28, 56 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.0085728844063"
## [1] "BEST method = 'both' PATH MEMBER = c( 28, 56 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.0085728844063"

## Package: RandomWalker
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.2257661577086"
## [1] "BEST method = 'lin', seasonal.factor = c( 63 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.2257661577086"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 3.25568514794957"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 3.25568514794957"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.06234849163741"
## [1] "BEST method = 'both' PATH MEMBER = c( 63 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.06234849163741"

## Package: tidyAML
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 6.43697401810396"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 6.34962386146168"
## [1] "BEST method = 'lin', seasonal.factor = c( 84, 91 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 6.34962386146168"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.25366230586835"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 84, 91 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.25366230586835"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.99287515264327"
## [1] "BEST method = 'both' PATH MEMBER = c( 84, 91 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.99287515264327"

## Package: TidyDensity
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.74524832904839"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.47356558778286"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 56, 35 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.38286731954275"
## [1] "BEST method = 'lin', seasonal.factor = c( 63, 56, 35 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.38286731954275"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63, 56, 35 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.78422409893306"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63, 56, 35 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.78422409893306"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63, 56, 35 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.66678773858143"
## [1] "BEST method = 'both' PATH MEMBER = c( 63, 56, 35 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.66678773858143"

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Pre-Processing

Now we are going to do some basic pre-processing.

data_padded_tbl <- base_data %>%
  pad_by_time(
    .date_var  = date,
    .pad_value = 0
  )

# Get log interval and standardization parameters
log_params  <- liv(data_padded_tbl$value, limit_lower = 0, offset = 1, silent = TRUE)
limit_lower <- log_params$limit_lower
limit_upper <- log_params$limit_upper
offset      <- log_params$offset

data_liv_tbl <- data_padded_tbl %>%
  # Get log interval transform
  mutate(value_trans = liv(value, limit_lower = 0, offset = 1, silent = TRUE)$log_scaled)

# Get Standardization Params
std_params <- standard_vec(data_liv_tbl$value_trans, silent = TRUE)
std_mean   <- std_params$mean
std_sd     <- std_params$sd

data_transformed_tbl <- data_liv_tbl %>%
  # get standardization
  mutate(value_trans = standard_vec(value_trans, silent = TRUE)$standard_scaled) %>%
  select(-value)

Since this is panel data we can follow one of two different modeling strategies. We can search for a global model in the panel data or we can use nested forecasting finding the best model for each of the time series. Since we only have 5 panels, we will use nested forecasting.

To do this we will use the nest_timeseries and split_nested_timeseries functions to create a nested tibble.

horizon <- 4*7

nested_data_tbl <- data_transformed_tbl %>%
    
    # 1. Extending: We'll predict n days into the future.
    extend_timeseries(
        .id_var        = package,
        .date_var      = date,
        .length_future = horizon
    ) %>%
    
    # 2. Nesting: We'll group by id, and create a future dataset
    #    that forecasts n days of extended data and
    #    an actual dataset that contains n*2 days
    nest_timeseries(
        .id_var        = package,
        .length_future = horizon
        #.length_actual = horizon*2
    ) %>%
    
   # 3. Splitting: We'll take the actual data and create splits
   #    for accuracy and confidence interval estimation of n das (test)
   #    and the rest is training data
    split_nested_timeseries(
        .length_test = horizon
    )

nested_data_tbl
## # A tibble: 8 × 4
##   package       .actual_data         .future_data      .splits          
##   <fct>         <list>               <list>            <list>           
## 1 healthyR.data <tibble [1,650 × 2]> <tibble [28 × 2]> <split [1622|28]>
## 2 healthyR      <tibble [1,644 × 2]> <tibble [28 × 2]> <split [1616|28]>
## 3 healthyR.ts   <tibble [1,588 × 2]> <tibble [28 × 2]> <split [1560|28]>
## 4 healthyverse  <tibble [1,558 × 2]> <tibble [28 × 2]> <split [1530|28]>
## 5 healthyR.ai   <tibble [1,383 × 2]> <tibble [28 × 2]> <split [1355|28]>
## 6 TidyDensity   <tibble [1,234 × 2]> <tibble [28 × 2]> <split [1206|28]>
## 7 tidyAML       <tibble [842 × 2]>   <tibble [28 × 2]> <split [814|28]> 
## 8 RandomWalker  <tibble [264 × 2]>   <tibble [28 × 2]> <split [236|28]>

Now it is time to make some recipes and models using the modeltime workflow.

Modeltime Workflow

Recipe Object

recipe_base <- recipe(
  value_trans ~ date
  , data = extract_nested_test_split(nested_data_tbl)
  )

recipe_base

recipe_date <- recipe_base %>%
    step_mutate(date = as.numeric(date))

Models

# Models ------------------------------------------------------------------

# Auto ARIMA --------------------------------------------------------------

model_spec_arima_no_boost <- arima_reg() %>%
  set_engine(engine = "auto_arima")

wflw_auto_arima <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_arima_no_boost)

# NNETAR ------------------------------------------------------------------

model_spec_nnetar <- nnetar_reg(
  mode              = "regression"
  , seasonal_period = "auto"
) %>%
  set_engine("nnetar")

wflw_nnetar <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_nnetar)

# TSLM --------------------------------------------------------------------

model_spec_lm <- linear_reg() %>%
  set_engine("lm")

wflw_lm <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_lm)

# MARS --------------------------------------------------------------------

model_spec_mars <- mars(mode = "regression") %>%
  set_engine("earth")

wflw_mars <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_mars)

Nested Modeltime Tables

nested_modeltime_tbl <- modeltime_nested_fit(
  # Nested Data
  nested_data = nested_data_tbl,
   control = control_nested_fit(
     verbose = TRUE,
     allow_par = FALSE
   ),
  # Add workflows
  wflw_auto_arima,
  wflw_lm,
  wflw_mars,
  wflw_nnetar
)
nested_modeltime_tbl <- nested_modeltime_tbl[!is.na(nested_modeltime_tbl$package),]

Model Accuracy

nested_modeltime_tbl %>%
  extract_nested_test_accuracy() %>%
  filter(!is.na(package)) %>%
  knitr::kable()
package .model_id .model_desc .type mae mape mase smape rmse rsq
healthyR.data 1 ARIMA Test 0.5855370 102.30733 0.6266358 128.70690 0.8020992 0.2055497
healthyR.data 2 LM Test 0.6377634 206.75981 0.6825279 123.39294 0.7939722 0.0044239
healthyR.data 3 EARTH Test 0.6576065 138.72253 0.7037639 146.84330 0.8625510 0.0044239
healthyR.data 4 NNAR Test 0.7156268 95.18227 0.7658566 168.71399 0.9708544 0.0169405
healthyR 1 ARIMA Test 0.7148223 123.00235 0.8703759 164.91372 0.8893949 0.0557124
healthyR 2 LM Test 0.6793562 97.70083 0.8271919 167.53139 0.8648480 0.0502272
healthyR 3 EARTH Test 0.6345182 128.86998 0.7725966 134.83236 0.7845044 0.0502272
healthyR 4 NNAR Test 0.7000701 149.57695 0.8524134 166.65682 0.8571585 0.0245626
healthyR.ts 1 ARIMA Test 0.6372057 102.92148 0.8125609 154.61933 0.7857825 0.0276328
healthyR.ts 2 LM Test 0.9049160 161.96352 1.1539436 154.63168 1.1203716 0.0276328
healthyR.ts 3 EARTH Test 0.5489115 157.42151 0.6999687 93.41615 0.6972032 0.0276328
healthyR.ts 4 NNAR Test 0.7674924 109.87067 0.9787018 175.14898 0.9695342 0.0003261
healthyverse 1 ARIMA Test 0.5973861 142.79604 1.0699211 78.62738 0.7592503 0.0141880
healthyverse 2 LM Test 0.5832757 147.96670 1.0446493 75.66541 0.7129084 0.0305761
healthyverse 3 EARTH Test 0.5890906 119.70138 1.0550638 78.17111 0.7650496 NA
healthyverse 4 NNAR Test 0.6661535 100.58549 1.1930838 92.55448 0.8604255 0.0246351
healthyR.ai 1 ARIMA Test 0.6395329 110.72057 0.9745449 172.58049 0.7969351 0.0234194
healthyR.ai 2 LM Test 0.5678213 90.64147 0.8652681 124.13721 0.7337760 0.0463945
healthyR.ai 3 EARTH Test 1.5170939 772.28622 2.3118063 117.30769 1.7342538 0.0463945
healthyR.ai 4 NNAR Test 0.5892327 130.05376 0.8978955 125.50746 0.7586005 0.1139031
TidyDensity 1 ARIMA Test 0.4935984 172.03605 1.0726726 112.53752 0.6396590 0.0239366
TidyDensity 2 LM Test 0.6380096 267.23984 1.3865022 119.11747 0.8023462 0.0025582
TidyDensity 3 EARTH Test 0.4761721 161.41729 1.0348023 111.38477 0.6208872 0.0025582
TidyDensity 4 NNAR Test 0.4241940 110.95388 0.9218449 121.39702 0.5371477 0.0072082
tidyAML 1 ARIMA Test 0.8063876 130.51856 0.8517556 101.19456 1.1166030 0.0011514
tidyAML 2 LM Test 0.7847263 124.73835 0.8288757 100.31402 1.0904809 0.2796813
tidyAML 3 EARTH Test 1.2695063 274.06927 1.3409298 120.40715 1.4888505 0.2796813
tidyAML 4 NNAR Test 0.7546819 114.02068 0.7971410 100.72009 1.0658945 0.0064640
RandomWalker 1 ARIMA Test 1.1015081 120.86909 0.6021124 123.70022 1.4039810 0.0172449
RandomWalker 2 LM Test 1.2002443 118.06846 0.6560841 191.16879 1.3687606 0.0123125
RandomWalker 3 EARTH Test 4.6809575 1181.24558 2.5587307 165.75031 5.2047281 0.0123125
RandomWalker 4 NNAR Test 1.1558392 181.07405 0.6318112 156.68751 1.3411679 0.0401079

Plot Models

nested_modeltime_tbl %>%
  extract_nested_test_forecast() %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_show  = FALSE,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")

Best Model

best_nested_modeltime_tbl <- nested_modeltime_tbl %>%
  modeltime_nested_select_best(
    metric = "rmse",
    minimize = TRUE,
    filter_test_forecasts = TRUE
  )

best_nested_modeltime_tbl %>%
  extract_nested_best_model_report()
## # Nested Modeltime Table
## 

## # A tibble: 8 × 10
##   package      .model_id .model_desc .type   mae  mape  mase smape  rmse     rsq
##   <fct>            <int> <chr>       <chr> <dbl> <dbl> <dbl> <dbl> <dbl>   <dbl>
## 1 healthyR.da…         2 LM          Test  0.638 207.  0.683 123.  0.794 0.00442
## 2 healthyR             3 EARTH       Test  0.635 129.  0.773 135.  0.785 0.0502 
## 3 healthyR.ts          3 EARTH       Test  0.549 157.  0.700  93.4 0.697 0.0276 
## 4 healthyverse         2 LM          Test  0.583 148.  1.04   75.7 0.713 0.0306 
## 5 healthyR.ai          2 LM          Test  0.568  90.6 0.865 124.  0.734 0.0464 
## 6 TidyDensity          4 NNAR        Test  0.424 111.  0.922 121.  0.537 0.00721
## 7 tidyAML              4 NNAR        Test  0.755 114.  0.797 101.  1.07  0.00646
## 8 RandomWalker         4 NNAR        Test  1.16  181.  0.632 157.  1.34  0.0401
best_nested_modeltime_tbl %>%
  extract_nested_test_forecast() %>%
  #filter(!is.na(.model_id)) %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_alpha = 0.2,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")

Refitting and Future Forecast

Now that we have the best models, we can make our future forecasts.

nested_modeltime_refit_tbl <- best_nested_modeltime_tbl %>%
    modeltime_nested_refit(
        control = control_nested_refit(verbose = TRUE)
    )
nested_modeltime_refit_tbl
## # Nested Modeltime Table
## 

## # A tibble: 8 × 5
##   package       .actual_data .future_data .splits           .modeltime_tables 
##   <fct>         <list>       <list>       <list>            <list>            
## 1 healthyR.data <tibble>     <tibble>     <split [1622|28]> <mdl_tm_t [1 × 5]>
## 2 healthyR      <tibble>     <tibble>     <split [1616|28]> <mdl_tm_t [1 × 5]>
## 3 healthyR.ts   <tibble>     <tibble>     <split [1560|28]> <mdl_tm_t [1 × 5]>
## 4 healthyverse  <tibble>     <tibble>     <split [1530|28]> <mdl_tm_t [1 × 5]>
## 5 healthyR.ai   <tibble>     <tibble>     <split [1355|28]> <mdl_tm_t [1 × 5]>
## 6 TidyDensity   <tibble>     <tibble>     <split [1206|28]> <mdl_tm_t [1 × 5]>
## 7 tidyAML       <tibble>     <tibble>     <split [814|28]>  <mdl_tm_t [1 × 5]>
## 8 RandomWalker  <tibble>     <tibble>     <split [236|28]>  <mdl_tm_t [1 × 5]>
nested_modeltime_refit_tbl %>%
  extract_nested_future_forecast() %>%
  mutate(across(.value:.conf_hi, .fns = ~ standard_inv_vec(
    x    = .,
    mean = std_mean,
    sd   = std_sd
  )$standard_inverse_value)) %>%
  mutate(across(.value:.conf_hi, .fns = ~ liiv(
    x = .,
    limit_lower = limit_lower,
    limit_upper = limit_upper,
    offset      = offset
  )$rescaled_v)) %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_alpha = 0.2,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")