bad.go

paramlist := map[string]params{
    "one": &params{ ... },
    "two": &params{ ... },
    "three": &params{ ... },
}
results := make(map[string]result, len(paramlist))
for k, v := range paramlist {
    wg.Add()
    go func(label string, myparams param) {
        defer wg.Done()
        // something that causes a result to be created
        results[label] = result
    }(k, v)
}
wg.Wait()
// at this point, results is a complete map[string]result

good.go

c := make(chan resultEnvelope)
paramlist := map[string]params{
    "one": &params{ ... },
    "two": &params{ ... },
    "three": &params{ ... },
}
for k, v := range paramlist {
    go func(label string, myparams param) {
        // something that causes a result to be created
        c <- resultEnvelope{Key: label, Value: result}
    }(k, v)
}
results := make(map[string]result, len(paramlist))
for _, envelope := range c {
    results[envelope.Key] = envelope.Value
    if received == len(paramlist) {
        break
    }
}
// at this point, results is a complete map[string]result.