socialmixr

• New rebin_ages() rebins a population table to a coarser set of age groups by summing. It operates on an age column of age-group labels (as produced by limits_to_age_groups() or assign_age_groups()) and returns the same form, so it composes directly with the post-processing functions. It only coarsens: requesting age groups finer than the population data is an error, since splitting a band would require assuming a within-band age distribution.
• New align_ages() aligns a population table to a contact matrix's groupings, returning the survey_pop data frame that symmetrise(), split_matrix() and per_capita() expect. Supply population with an age column of age-group label, plus a column per other grouping; align_ages() coarsens age to the matrix's age groups within each combination of the other groupings (via rebin_ages()) and aggregates categorical groupings by exact name. The population must be at least as fine as the matrix's age groups. A typical workflow is result |> symmetrise(survey_pop = align_ages(population, result)) (#319).
• The contact_matrix S3 object now carries a groupings field — the list of grouping triples that produced its matrix. Used internally by the multi-grouping post-processing functions; users can read it to introspect the matrix's structure (#319).
• New flatten() returns a T x T matrix view of a multi-grouping contact matrix — Manna et al.'s generalised representation, with colon-joined dim labels (e.g. "[0,5):F"). For single-grouping matrices it returns the matrix unchanged (#319).
• plot() and as.matrix() now work on multi-grouping contact matrices, operating on the flattened T x T view. matrix_plot() no longer assumes a square matrix, so non-square flattened matrices plot correctly (#321).
• New vignette, *Contact matrices across more than one grouping*, with recipes for building, flattening, plotting and post-processing matrices over several groupings (#322).
• weigh() gains a new canonical target shape: a two-column data frame whose key column matches by is joined and multiplied into weight. This makes recipes like weigh(survey, "country", target = ...) natural. The previous silent dispatch on a population data frame (a target data frame with lower.age.limit/population and no column matching by) is soft-deprecated; use the new weigh_by_age() for the same effect with an explicit name. weigh_by_age() takes a reference population with an age column of age-group labels and a population column. New weigh_by_dayofweek() is a thin wrapper around the existing 5/2 split. weigh()'s named vector and groups paths are unchanged (#314).

Deprecations

• Exported function names now spell "age groups" consistently as age_groups (snake_case), matching assign_age_groups(). reduce_agegroups(), limits_to_agegroups() and agegroups_to_limits() are renamed to reduce_age_groups(), limits_to_age_groups() and age_groups_to_limits(); the old names remain as deprecated aliases that warn (#331).
• Interpolating population data to age groups finer than the data itself is deprecated. contact_matrix() (when it adjusts demographic data to the requested age groups) and pop_age() still do it but now warn, and it will error in a future release. Supply population data at least as fine as the requested age groups. The new rebin_ages() and align_ages() never interpolate: they error on finer requests.
• pop_age() is deprecated in favour of rebin_ages() and warns; it will be removed in a future release (#328).
• Advance deprecation cycle (#312). wpp_age(), wpp_countries(), and survey_country_population() are deprecated (warn) — all three are thin layers over wpp2017, which is on its way out. Construct a data.frame with columns lower.age.limit and population from a current source (e.g. the wpp2024 package from GitHub) and pass it to contact_matrix() via survey_pop instead. The implicit population lookup in contact_matrix() (when survey_pop is not given but symmetric, split, per_capita, weigh_age, or return_demography is set) keeps the warning introduced in 0.6.0 with a sharper "will error in a future release" message. wpp2017 remains in Imports for now, so this lookup keeps working; it will move to Suggests in a later release once reverse dependencies have migrated. The following are now defunct (deprecate_stop): survey(), check(), get_survey(), download_survey(), list_surveys(), survey_countries(), get_citation(), and the missing_contact_age = "sample" option on assign_age_groups() and contact_matrix(). The dotted argument names (age.limits, survey.pop, country.column, etc.) on contact_matrix(), pop_age(), clean(), and as_contact_survey() remain deprecated and warn, rather than becoming defunct, so downstream packages still using them keep working while they migrate. Bogus "1.0.0" versions on the survey() and check() deprecation messages have been corrected.

Bug fixes

• load_survey() now errors clearly when given no files (e.g. an empty vector or NULL from a failed download) instead of raising an opaque invalid 'file' argument.

Internal

• Removed the air formatter: air.toml, the style.yaml format-suggestion workflow, and the VS Code formatter settings. lintr continues to run on changed files, and indentation_linter is re-enabled (with a hanging-indent style) to keep linting indentation now that air no longer handles it.